[ci] Set release action owner as flutter (#4091)

diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index ecda750..f6753e5 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -6,6 +6,7 @@
 
 jobs:
   release:
+    if: github.repository_owner == 'flutter'
     name: release
     runs-on: ubuntu-latest
     steps: