CI runs on pull request because it runs on push. Remove the pull request run.

Author: partiallyordered

.github/workflows/smoke-test-kustomizations.yaml

@@ -1,11 +1,10 @@
 name: "Smoke test manifests"
 on:
-  pull_request:
   push:
   workflow_dispatch:
     inputs:
       debug_enabled:
-        description: 'Run the build with tmate debugging enabled (https://github.com/marketplace/actions/debugging-with-tmate)'     
+        description: 'Run the build with tmate debugging enabled (https://github.com/marketplace/actions/debugging-with-tmate)'
         required: false
         default: false
 jobs: