[GHA] Pin workflow to repository.

.github/workflows/build.yml

@@ -14,6 +14,8 @@ concurrency:
 
 jobs:
   excludes:
+    name: 'Excludes'
+    if: github.repository == 'signalwire/freeswitch'
     runs-on: ubuntu-latest
     outputs:
       deb: ${{ steps.deb.outputs.excludes }}
@@ -47,6 +49,7 @@ jobs:
 
   deb:
     name: 'DEB'
+    if: github.repository == 'signalwire/freeswitch'
     permissions:
       id-token: write
       contents: read