maint: avoid double execution of GA (second attempt)

Author: oesteban

.github/workflows/docs-build-pr.yml

@@ -7,7 +7,7 @@ on:
 
 jobs:
   build:
-    if: "!contains(github.event.head_commit.message, '[skip ci]')"
+    if: "github.repository_owner != 'nipreps' && !contains(github.event.head_commit.message, '[skip ci]')"
     runs-on: ubuntu-latest
 
     steps: