ci: gate upstream release workflows on go-gitea/gitea

The 3 release workflows (nightly, RC, version) target
namespace-profile-gitea-* runners that exist only on upstream's
Namespace.so CI cloud. On forks they queue forever waiting for
labels that never appear. Gate each job on github.repository, matching
the existing gate on cron-*.yml. Fork-only diff.

.github/workflows/release-nightly.yml

@@ -10,6 +10,7 @@ concurrency:
 
 jobs:
   nightly-binary:
+    if: github.repository == 'go-gitea/gitea'
     runs-on: namespace-profile-gitea-release-binary
     permissions:
       contents: read
@@ -62,6 +63,7 @@ jobs:
           aws s3 sync dist/release s3://${{ secrets.AWS_S3_BUCKET }}/gitea/${{ steps.clean_name.outputs.branch }} --no-progress
 
   nightly-container:
+    if: github.repository == 'go-gitea/gitea'
     runs-on: namespace-profile-gitea-release-docker
     permissions:
       contents: read

.github/workflows/release-tag-rc.yml

@@ -11,6 +11,7 @@ concurrency:
 
 jobs:
   binary:
+    if: github.repository == 'go-gitea/gitea'
     runs-on: namespace-profile-gitea-release-binary
     permissions:
       contents: read
@@ -72,6 +73,7 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.RELEASE_TOKEN }}
 
   container:
+    if: github.repository == 'go-gitea/gitea'
     runs-on: namespace-profile-gitea-release-docker
     permissions:
       contents: read

.github/workflows/release-tag-version.yml

@@ -13,6 +13,7 @@ concurrency:
 
 jobs:
   binary:
+    if: github.repository == 'go-gitea/gitea'
     runs-on: namespace-profile-gitea-release-binary
     permissions:
       contents: read
@@ -75,6 +76,7 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.RELEASE_TOKEN }}
 
   container:
+    if: github.repository == 'go-gitea/gitea'
     runs-on: namespace-profile-gitea-release-docker
     permissions:
       contents: read