fix: chore(container): add pullrequest event to container build workflow trigger

Author: kaiehrhardt

.github/workflows/container-build.yml

@@ -5,6 +5,9 @@ on:
       - '**'
   schedule:
     - cron: '0 0 * * *'
+  pull_request:
+    paths:
+      - 'Dockerfile.ci'
 jobs:
   container-build:
     runs-on: ubuntu-latest