convert circleci workflows to github actions

.github/actions/check-torch/action.yml

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+name: check-torch
+description: 'Check PyTorch version'
+inputs:
+  major:
+    description: 'Major version of PyTorch'
+    required: true
+  minor:
+    description: 'Minor version of PyTorch'
+    required: true
+runs:
+  using: composite
+  steps:
+    - name: Check the installed PyTorch version
+      shell: bash -el {0}
+      run: |
+        which python
+
+        python -c 'import torch; print("Torch version:", torch.__version__)'
+        python -c 'import torch; assert torch.__version__ > ( <<parameters.major>>,  <<parameters.minor>>), "wrong torch version"'
+        python -m torch.utils.collect_env
+        wget -O ~/venv/check_version.py https://raw.githubusercontent.com/min-xu-ai/check_verion/main/check_version.py

.github/actions/install-dep/action.yml

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+name: install-dep
+description: 'Install dependencies'
+runs:
+  using: composite
+  steps:
+    - name: Install Dependencies with torch nightly
+      shell: bash -el {0}
+      run: |
+        # for faster builds
+        conda install ninja
+        echo "Ninja version $(ninja --version)"
+
+        conda install pytorch torchvision torchaudio pytorch-cuda=11.8 -c pytorch -c nvidia -q
+
+        python -m pip install cmake
+        python -m pip install -r requirements-benchmark.txt --progress-bar off

.github/actions/install-repo/action.yml

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+name: install-repo
+description: 'Install repository'
+runs:
+  using: composite
+  steps:
+    - name: Install Repository
+      shell: bash -el {0}
+      run: |
+        python -m pip install -v -e .
+
+        # Test import.
+        python -c 'import sys; sys.path = sys.path[1:]; import xformers'
+        ls xformers
+        python -m xformers.info

.github/actions/run-doc-build/action.yml

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+name: run-doc-build
+description: 'Run documentation build'
+runs:
+  using: composite
+  steps:
+    - name: Testing doc build
+      shell: bash -el {0}
+      run: |
+        cd docs
+        # Don't install PyTorch as we already pulled it from conda, and we'd risk having two conflicting versions
+        python -m pip install $(grep -ivE "^#|^torch" requirements.txt)
+        make help
+        make singlehtml | tee make.out
+        ! tail make.out | grep -q warning

.github/actions/run-unittests/action.yml

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+name: run-unittests
+description: 'Run unit tests'
+runs:
+  using: composite
+  steps:
+    - name: Run Unit Tests
+      shell: bash -el {0}
+      run: |
+        python -m pytest --random-order-bucket=global --junitxml=test-results/junit.xml --verbose --maxfail=20 tests

.github/actions/setup-miniconda/action.yml

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+name: setup-miniconda
+description: 'Setup Miniconda'
+inputs:
+  python-version:
+    description: 'Python version to install'
+    default: '3.8'
+  auto-update-conda:
+    description: 'Whether to update conda'
+    default: 'true'
+  activate-environment:
+    description: 'Name of the conda environment to activate'
+    default: 'xformers'
+outputs:
+  cache-hit:
+    description: 'Whether the cache was restored'
+    value: ${{ steps.cache.outputs.cache-hit }}
+runs:
+  using: composite
+  steps:
+    # use my fork of the conda-incubator/setup-miniconda@v3 action
+    # until this PR is merged: https://github.com/conda-incubator/setup-miniconda/pull/350
+    - name: Setup miniconda
+      uses: robandpdx-org/setup-miniconda@fix-conda-env-var
+      with:
+        python-version: ${{ inputs.python-version }}
+        auto-update-conda: ${{ inputs.auto-update-conda }}
+        activate-environment: ${{ inputs.activate-environment }}
+    - name: Get Date
+      id: get-date
+      run: echo "today=$(/bin/date -u '+%Y%m%d')" >> $GITHUB_OUTPUT
+      shell: bash
+    - name: Cache Conda env
+      uses: actions/cache@v3
+      with:
+        path: ${{ env.CONDA }}/envs
+        key:
+          conda-${{ runner.os }}-${{ runner.arch }}-${{steps.get-date.outputs.today }}-${{ env.CACHE_NUMBER }}
+      env:
+        CACHE_NUMBER: '0'
+      id: cache
+    - name: Conda info
+      shell: bash -el {0}
+      run: |
+        conda config --set always_yes yes
+        conda install pip
+        conda info -a

.github/workflows/test.yml

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+name: Tests
+
+on:
+  pull_request:
+    branches:
+      - main
+    # paths:
+    #   - 'xformers/**'
+    #   - '.github/workflows/test.yml'
+    #   - 'setup.py'
+    #   - 'requirements.*'
+    #   - '.circleci/**'
+jobs:
+  cpu_tests_py38:
+    runs-on: 4-core-ubuntu-latest
+    env:
+      MAX_JOBS: "4"
+    defaults:
+      run:
+        shell: bash -el {0}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: recursive
+      - name: Remove internal components, as they require GPU
+        run: |
+          mkdir -p .github/sync.fairinternal
+          touch .github/sync.fairinternal/ossify.sh
+          chmod +x .github/sync.fairinternal/ossify.sh
+          .github/sync.fairinternal/ossify.sh
+      - name: Setup Miniconda
+        id: setup-miniconda
+        uses: ./github/actions/setup-miniconda
+      - name: Install Dependencies
+        if: steps.setup-miniconda.outputs.cache-hit != 'true'
+        uses: ./github/actions/install-dep
+      - name: Check PyTorch version
+        uses: ./github/actions/check-torch
+        with:
+          major: 2
+          minor: 1
+      - name: Run unit tests
+        uses: ./github/actions/run-unittests
+      - name: Run doc build
+        uses: ./github/actions/run-doc-build
+      - name: Store test results
+        uses: actions/upload-artifact@v4
+        with:
+          name: test-results
+          path: test-results