.github: drop this job from regular branches and run after merge

We want Reggie to take most of the hits, then we sail in and build after
the PR has been merged so we can upload new "Nightly" images.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

.github/workflows/build.yml

@@ -1,22 +1,16 @@
 name: Bob the Builder
 
-#on:
-#  push:
-#    branches:
-#      - '*'
-#  pull_request:
-#    branches:
-#      - '*'
 on:
-  pull_request_review:
+  pull_request:
+    branches:
+      - main
     types:
-      - submitted
       - closed
   workflow_dispatch:
 
 jobs:
   build:
-    if: github.event.review.state == 'approved' || github.event_name == 'workflow_dispatch'
+    if: ${{ github.event.pull_request.merged }} || github.event_name == 'workflow_dispatch'
     name: Build ${{ matrix.platform }} ${{ matrix.variant }}
     runs-on: ubuntu-latest
     strategy: