Actions: Open a PR after each release to bump the patch version.

.github/workflows/release.yml

@@ -87,4 +87,25 @@ jobs:
           # Get the `vsix_path` and `ref_name` from the `prepare-artifacts` step above.
           asset_path: ${{ steps.prepare-artifacts.outputs.vsix_path }}
           asset_name: ${{ format('vscode-codeql-{0}.vsix', steps.prepare-artifacts.outputs.ref_name) }}
-          asset_content_type: application/zip
+          asset_content_type: application/zip
+
+      - name: Bump patch version
+        id: bump-patch-version
+        if: success()
+        run: |
+          cd extensions/ql-vscode
+          # Bump to the next patch version. Major or minor version bumps will have to be done manually.
+          # Record the next version number as an output of this step.
+          NEXT_VERSION="$(npm version patch)"
+          echo "::set-output name=next_version::$NEXT_VERSION"
+
+      - name: Create version bump PR
+        uses: peter-evans/create-pull-request@7531167f24e3914996c8d5110b5e08478ddadff9  # v1.8.0
+        if: success()
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          commit-message: Bump version to ${{ steps.bump-patch-version.outputs.next_version }}
+          title: Bump version to ${{ steps.bump-patch-version.outputs.next_version }}
+          body: This PR was automatically generated by the GitHub Actions release workflow in this repository.
+          branch: ${{ format('version/bump-to-{0}', steps.bump-patch-version.outputs.next_version) }}
+          branch-suffix: none