CI: Add once-a-week workflows to test 5.0.1 trunk

These workflows use the custom compiler path so that:
- it works on Windows (there is no opam package for that branch
  upstream)
- it regularly tests that our custom compiler system keeps working

Author: shym

.github/workflows/linux-501-bytecode-trunk-workflow.yml

@@ -0,0 +1,16 @@
+name: Bytecode trunk
+
+on:
+  schedule:
+    # Every Monday morning, at 1:11 UTC
+    - cron: '11 1 * * 1'
+
+jobs:
+  build:
+    uses: ./.github/workflows/common.yml
+    with:
+      compiler:                'ocaml-variants.5.0.1+trunk,ocaml-option-bytecode-only'
+      compiler_git_ref:        'refs/heads/5.0'
+      custom_compiler_version: '5.0.1+trunk'
+      custom_compiler_src:     'https://github.com/ocaml/ocaml/archive/5.0.tar.gz'
+      timeout:                 360

.github/workflows/linux-501-debug-trunk-workflow.yml

@@ -0,0 +1,18 @@
+name: Linux 5.0 trunk debug
+
+on:
+  schedule:
+    # Every Monday morning, at 1:11 UTC
+    - cron: '11 1 * * 1'
+
+jobs:
+  build:
+    uses: ./.github/workflows/common.yml
+    with:
+      compiler:                'ocaml-variants.5.0.1+trunk'
+      compiler_git_ref:        'refs/heads/5.0'
+      custom_compiler_version: '5.0.1+trunk'
+      custom_compiler_src:     'https://github.com/ocaml/ocaml/archive/5.0.tar.gz'
+      dune_profile:            'debug-runtime'
+      runparam:                'v=0,V=1'
+      timeout:                 360

.github/workflows/linux-501-trunk-workflow.yml

@@ -0,0 +1,16 @@
+name: Linux 5.0 trunk
+
+on:
+  schedule:
+    # Every Monday morning, at 1:11 UTC
+    - cron: '11 1 * * 1'
+
+jobs:
+  build:
+    uses: ./.github/workflows/common.yml
+    with:
+      compiler:                'ocaml-variants.5.0.1+trunk'
+      compiler_git_ref:        'refs/heads/5.0'
+      custom_compiler_version: '5.0.1+trunk'
+      custom_compiler_src:     'https://github.com/ocaml/ocaml/archive/5.0.tar.gz'
+      timeout:                 360

.github/workflows/macosx-501-trunk-workflow.yml

@@ -0,0 +1,16 @@
+name: macOS 5.0 trunk
+
+on:
+  schedule:
+    # Every Monday morning, at 1:11 UTC
+    - cron: '11 1 * * 1'
+
+jobs:
+  build:
+    uses: ./.github/workflows/common.yml
+    with:
+      runs_on:                 'macos-latest'
+      compiler:                'ocaml-variants.5.0.1+trunk'
+      compiler_git_ref:        'refs/heads/5.0'
+      custom_compiler_version: '5.0.1+trunk'
+      custom_compiler_src:     'https://github.com/ocaml/ocaml/archive/5.0.tar.gz'

.github/workflows/windows-501-trunk-bytecode-workflow.yml

@@ -0,0 +1,17 @@
+name: Win bytecode 5.0 trunk
+
+on:
+  schedule:
+    # Every Monday morning, at 1:11 UTC
+    - cron: '11 1 * * 1'
+
+jobs:
+  build:
+    uses: ./.github/workflows/common.yml
+    with:
+      runs_on:                 'windows-latest'
+      compiler:                'ocaml-variants.5.0.1+trunk,ocaml-option-mingw,ocaml-option-bytecode-only'
+      compiler_git_ref:        'refs/heads/5.0'
+      custom_compiler_version: '5.0.1+trunk'
+      custom_compiler_src:     'https://github.com/ocaml/ocaml/archive/5.0.tar.gz'
+      timeout:                 360

.github/workflows/windows-501-trunk-workflow.yml

@@ -0,0 +1,17 @@
+name: Windows 5.0 trunk
+
+on:
+  schedule:
+    # Every Monday morning, at 1:11 UTC
+    - cron: '11 1 * * 1'
+
+jobs:
+  build:
+    uses: ./.github/workflows/common.yml
+    with:
+      runs_on:                 'windows-latest'
+      compiler:                'ocaml-variants.5.0.1+trunk,ocaml-option-mingw'
+      compiler_git_ref:        'refs/heads/5.0'
+      custom_compiler_version: '5.0.1+trunk'
+      custom_compiler_src:     'https://github.com/ocaml/ocaml/archive/5.0.tar.gz'
+      timeout:                 360