Don't trigger CI on tag pushes

Tags should only be created on content which is already checked via
pushing on a branch (and by merging via a PR)

Author: masklinn

.github/workflows/ci.yml

@@ -2,6 +2,7 @@ name: CI
 
 on:
   push:
+    branches:
   pull_request:
 
 permissions: {}

.github/workflows/rs-checks.yml

@@ -3,6 +3,7 @@ name: rs checks
 on:
   pull_request:
   push:
+    branches:
 
 permissions: {}
 

.github/workflows/zizmor.yml

@@ -2,6 +2,7 @@ name: Zizmor
 
 on:
   push:
+    branches:
   pull_request:
 
 permissions: {}