Avoid templating GitHub Actions workflow (#7952)

* Avoid templating GitHub Actions workflow

GitHub Actions workflow have sufficient power to express what we need.
We don't need to maintain and additional templating solution on top.

* Add GHC 9.2, bump bounds, fix syntax

* Switch to official haskell image

* Always run cli tests for ghc 8.2 and above

* Remove step to regenerate GitHub Actions workflows

* Fix missed reference to GHC version

* Fix yaml syntax

* Fix type in the GHC version

* More CI changes

- Run bootstrap.yml on ubuntu-latest
- Use explicit matrix for linux.yml
- Drop containers in favour of haskell setup action
- Drop workaround for ancient git

* Remove unneeded package from CI setup

I belive this is only necessary to run `cabal man` which we do not in
the CI.

* Drop old GHCs from the CI

* Switch macos.yml to haskell/action/setup

Also add the same GHC versions as Linux.

* Simplify CI

- Remove cabal-plan, we actually never call it (I think)
- Remove vendored cabal-doctest
- Remove few stray allow-newer clauses no longer necessary, apparently

Originally done by @gbaz in PR #7907.

* Mark GHC 9.2.1 as experimental

* Remove reference to cabal-plan from validate.sh

* setup-haskell action already runs cabal update

* Add missing build matrix in test-windows-dogfood

* Replace cabal-plan list-bin with cabal list-bin

* Enable caching in the CI

* Fix typo

* Remove continue-on-error until I figure it out

* Keep naming consistent

* Temporarily disable 8.0.2 on macos

* Add missing step id

* Tweaks

Remove workaround for nektos/act, it accidentally sneaked in.

* More tweaks

* Tweaks

* Restore cabal-plan, temporarily mark everything experimental

cabal list-bin doesn't seem to work like cabal-plan does.

* Tweaks

* Ensure cabal-plan executable gets built

* Install automake on MacOS

* Tweaks

* Tweaks

Link experimental flags to relative GitHub issues

* Fix typo

.github/workflows/bootstrap.yml

@@ -1,10 +1,5 @@
-# This file is auto-generated
-#
-# To regenerate it run
-#
-#     make github-actions
-#
 name: Bootstrap
+
 on:
   push:
     branches:
@@ -15,37 +10,21 @@ on:
       - created
 
 jobs:
-  bootstrap-linux:
-    name: Bootstrap on Linux
-    runs-on: ubuntu-18.04
-    steps:
-      - uses: actions/checkout@v2
-      - name: bootstrap.py
-        run: |
-          ghcup config set cache true
-          ghcup install ghc 8.10.7
-          python3 bootstrap/bootstrap.py -w $(ghcup whereis ghc 8.10.7) -d bootstrap/linux-8.10.7.json
-
-      - name: Smoke test
-        run: |
-          _build/bin/cabal --version
-
-      - uses: actions/upload-artifact@v2
-        with:
-          name: cabal-linux-bootstrapped
-          path: _build/artifacts/*
-
-  bootstrap-macos:
-    name: Bootstrap on macOS
-    runs-on: macos-latest
+  bootstrap:
+    strategy:
+      matrix:
+        os:
+          - ubuntu-latest
+          - macos-latest
+    name: Bootstrap ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v2
-
-      # We use linux dependencies
       - name: bootstrap.py
         run: |
           ghcup config set cache true
           ghcup install ghc 8.10.7
+          # We use linux dependencies also on macos
           python3 bootstrap/bootstrap.py -w $(ghcup whereis ghc 8.10.7) -d bootstrap/linux-8.10.7.json
 
       - name: Smoke test
@@ -54,5 +33,5 @@ jobs:
 
       - uses: actions/upload-artifact@v2
         with:
-          name: cabal-macos-bootstrapped
+          name: cabal-${{ matrix.os }}-bootstrapped
           path: _build/artifacts/*