feat: Test build matrix

Author: erikmd

.github/workflows/build-coq-demo.yml

@@ -4,12 +4,12 @@ name: CI
 
 # Controls when the action will run.
 # cf. https://help.github.com/en/actions/configuring-and-managing-workflows/configuring-a-workflow#filtering-for-specific-branches-tags-and-paths
-# Triggers the workflow on push events or pull request events for the
+# Triggers the workflow on all push events or pull request events for the
 # master branch only:
 on:
   push:
     branches:
-      - master
+      - '**'
   pull_request:
     branches:
       - master
@@ -22,17 +22,25 @@ jobs:
     # the OS must be GNU/Linux to be able to use the docker-coq-action
     runs-on: ubuntu-latest
 
+    strategy:
+      matrix:
+        coq_version: ['8.11', 'dev']
+        ocaml_version: ['4.07-flambda', '4.09-flambda']
+      # at most 20 concurrent jobs per free account
+      # cf. https://help.github.com/en/actions/reference/workflow-syntax-for-github-actions#usage-limits
+      max-parallel: 4
+
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
     # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
     - uses: actions/checkout@v2
 
-    - uses: erikmd/docker-coq-action@alpha
+    - uses: erikmd/docker-coq-action@simplify-entrypoint
       id: docker-coq-action
       with:
         opam_file: 'coq-demo.opam'
-        coq_version: '8.11'
-        ocaml_version: '4.07-flambda'
+        coq_version: ${{ matrix.coq_version }}
+        ocaml_version: ${{ matrix.ocaml_version }}
         custom_script: |
           startGroup Print opam config
             opam config list; opam repo list; opam list
@@ -42,6 +50,8 @@ jobs:
             opam update -y
           endGroup
           startGroup Build
+            variable=OK
+            echo "$variable"
             opam install -y -v -j 2 $PACKAGE
             opam list
           endGroup