Revert "ci: trigger push build action after tag creation"

This reverts commit c53304c.

After experimenting with this release, we have found that the
`workflow_run` action source doesn't work for branches. The
documentation was updated with this PR and has more detail.
github/docs#531

For now, we will revert back to using on.push.tags = ["v*"]

Signed-off-by: Blaine Gardner <blaine.gardner@redhat.com>

.github/workflows/push-build.yaml

@@ -4,9 +4,8 @@ on:
     branches:
       - master
       - release-*
-  workflow_run:
-    workflows: ["Tag"]
-    types: [completed]
+    tags:
+      - v*
 
 defaults:
   run:
@@ -16,12 +15,7 @@ defaults:
 jobs:
   push-image-to-container-registry:
     runs-on: ubuntu-18.04
-    # github.repository == 'rook/rook': for running the test only in 'rook/rook' repo
-    # github.event_name == 'push': This is for any push to master or release branches
-    # github.event.workflow_run.conclusion == 'success': For the tagged workflow completion
-    if: |
-      github.repository == 'rook/rook' &&
-      (github.event_name == 'push' || github.event.workflow_run.conclusion == 'success')
+    if: github.repository == 'rook/rook'
     steps:
       - name: checkout
         uses: actions/checkout@v2