Add GHA workflow to resolve Manifest file periodically

Author: penelopeysm

.github/workflows/resolve_manifest.yml

@@ -0,0 +1,46 @@
+# This action periodically runs Pkg.instantiate() and Pkg.resolve() on the
+# top-level environment. If this leads to a change in the Manifest.toml file,
+# it will open a PR to update the Manifest.toml file. This ensures that the
+# version of the Manifest in the repository is consistent with the version of the
+# Manifest used by the CI system (i.e. during the actual docs generation).
+#
+# See https://github.com/TuringLang/docs/issues/518 for motivation.
+
+name: Resolve Manifest
+on:
+  push:
+    branches:
+      - master
+  workflow_dispatch:
+
+jobs:
+  check-version:
+    runs-on: ubuntu-latest
+
+    permissions:
+      contents: write
+      pull-requests: write
+
+    env:
+      # Disable precompilation as it takes a long time and is not needed for this workflow
+      JULIA_PKG_PRECOMPILE_AUTO: 0
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Setup Julia
+        uses: julia-actions/setup-julia@v2
+        
+      - name: Instantiate and resolve
+        run: |
+          julia -e 'using Pkg; Pkg.instantiate(); Pkg.resolve()'
+
+      - name: Create a PR with suggested changes
+        id: create_pr
+        uses: peter-evans/create-pull-request@v6
+        with:
+          branch: resolve-manifest
+          commit-message: "Update Manifest.toml"
+          body: "This PR is automatically generated by the `resolve_manifest.yml` GitHub Action."
+          title: "Update Manifest.toml to match CI environment"