Fix insta-merge yamllint issues

Author: atheo89

.github/workflows/insta-merge.yaml

@@ -1,6 +1,7 @@
+---
 name: Insta Merge Konflux PRs
 
-on:
+on:  # yamllint disable-line rule:truthy
   pull_request:
     paths:
       - manifests/base/params-latest.env
@@ -25,4 +26,4 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ github.token }}
         run: |
-          gh pr merge --merge --admin ${{ github.event.pull_request.html_url }}
+          gh pr merge --merge --admin ${{ github.event.pull_request.html_url }}