chore: yarn install+build+lint+test action using for core

.github/actions/yarn-install-and-verify/action.yml

@@ -0,0 +1,37 @@
+name: Yarn Install Build Test and Lint
+
+inputs:
+  cache_id:
+    description: ID to use in order to cache yarn install
+    required: true
+  working_dir:
+    description: Directory in which to perform the yarn tasks
+    required: true
+
+runs:
+  using: composite
+  steps:
+    - uses: actions/cache@v2
+      with:
+        path: '**/node_modules'
+        key: ${{ inputs.cache_id }}-${{ runner.os }}-modules-${{ hashFiles('**/yarn.lock') }}
+
+    - name: Install modules
+      run: yarn install
+      working-directory: ${{ inputs.working_dir }}
+      shell: bash
+
+    - name: Build TypeScript 
+      run: yarn build
+      working-directory: ${{ inputs.working_dir }}
+      shell: bash
+
+    - name: Test TypeScript
+      run: yarn test
+      working-directory: ${{ inputs.working_dir }}
+      shell: bash
+
+    - name: Lint TypeScript 
+      run: yarn lint
+      working-directory: ${{ inputs.working_dir }}
+      shell: bash

.github/workflows/sdk-core.yml

@@ -0,0 +1,18 @@
+name: SDK Core
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+jobs:
+  build-lint-and-test-core:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v1
+      - uses: ./.github/actions/yarn-install-and-verify
+        with: 
+          cache_id: sdk-core  
+          working_dir: ./core/js