Allow CI builds for external contributors

This change enables external contributors to run CI builds after
approval from the repository maintainer.

.github/workflows/build.yml

@@ -1,4 +1,4 @@
-name: Kernel Build (Trusted)
+name: Kernel Build
 
 on: pull_request
 
@@ -6,7 +6,7 @@ jobs:
   build:
     name: Build
     runs-on: [self-hosted]
-    if: github.event.pull_request.head.repo.full_name == github.repository && !contains(github.event.head_commit.message, 'skip ci')
+    if: ${{ !contains(github.event.head_commit.message, 'skip ci') }}
     steps:
     - name: Clean Workspace
       run: rm -rf *.deb *.ddeb *.build *.buildinfo *.changes