Add manual trigger to CI workflow

Closes gh-1777

Author: eleftherias

.github/workflows/continuous-integration-workflow.yml

@@ -6,6 +6,7 @@ on:
       - 2.4.x
   schedule:
     - cron: '0 10 * * *' # Once per day at 10am UTC
+  workflow_dispatch: # Manual trigger
 
 env:
   GRADLE_ENTERPRISE_CACHE_USER: ${{ secrets.GRADLE_ENTERPRISE_CACHE_USER }}