Mark prereleases on Github

.github/actions/check-prerelease/action.yml

@@ -0,0 +1,21 @@
+name: Checks whether a version is a prerelease
+description: Checks whether a version is prerelease according to PEP440.
+inputs:
+  version:
+    description: Version number to check.
+    required: true
+outputs:
+  prerelease:
+    description: Whether the version number is a prerelease.
+    value: ${{ steps.check-prerelease.outputs.PRERELEASE }}
+runs:
+  using: composite
+  steps:
+    - name: Install packaging
+      run: pip install packaging
+      shell: bash
+
+    - name: Check if prerelease
+      id: check-prerelease
+      run: ./.github/actions/check-prerelease/check_prerelease.py ${{ inputs.version }} >> "$GITHUB_OUTPUT"
+      shell: bash

.github/actions/check-prerelease/check_prerelease.py

@@ -0,0 +1,17 @@
+#!/usr/bin/env python3
+
+import argparse
+
+from packaging.version import parse as parse_version
+
+if __name__ == "__main__":
+    arg_parser = argparse.ArgumentParser(
+        description="Check whether a version is a prerelease according to PEP440."
+    )
+    arg_parser.add_argument("version")
+    args = arg_parser.parse_args()
+
+    if parse_version(args.version).is_prerelease:
+        print("PRERELEASE=true")
+    else:
+        print("PRERELEASE=false")

.github/workflows/ci.yml

@@ -121,11 +121,18 @@ jobs:
         with:
           args: --standalone --wrap none -f rst -t gfm --output=release-body.md release-body.rst
 
+      - name: Check if prerelease
+        id: check-prerelease
+        uses: ./.github/actions/check-prerelease
+        with:
+          version: ${{ steps.version.outputs.version }}
+
       - name: Create GitHub release
         uses: softprops/action-gh-release@v1
         with:
           body_path: release-body.md
           tag_name: v${{ steps.version.outputs.version }}
+          prerelease: ${{ steps.check-prerelease.outputs.prerelease }}
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}