ci(ci): support workflow_dispatch for determine-version job

Allows the release pipeline to run when manually triggered via
workflow_dispatch, not just on push events.

Author: Mearman

.github/workflows/ci.yml

@@ -114,7 +114,7 @@ jobs:
   determine-version:
     runs-on: ubuntu-latest
     timeout-minutes: 5
-    if: github.ref == 'refs/heads/main' && github.event_name == 'push'
+    if: github.ref == 'refs/heads/main' && (github.event_name == 'push' || github.event_name == 'workflow_dispatch')
     outputs:
       next-version: ${{ steps.version.outputs.next-version }}
       should-release: ${{ steps.version.outputs.should-release }}