github actions: use shallow clone for kernel checkout

Author: bmastbergen

.github/workflows/build-check_x86_64.yml

@@ -33,9 +33,9 @@ jobs:
           PR_REPO_FULL_NAME: ${{ github.event.pull_request.head.repo.full_name }}
         run: |
           if [ "$PR_REPO_FULL_NAME" = "ctrliq/kernel-src-tree" ]; then
-            git clone --branch "$HEAD_REF" "https://oauth2:${GITHUB_TOKEN}@github.com/ctrliq/kernel-src-tree" kernel-src-tree
+            git clone --depth 1 --branch "$HEAD_REF" "https://oauth2:${GITHUB_TOKEN}@github.com/ctrliq/kernel-src-tree" kernel-src-tree
           else
-            git clone --branch "$HEAD_REF" "$PR_CLONE_URL" kernel-src-tree
+            git clone --depth 1 --branch "$HEAD_REF" "$PR_CLONE_URL" kernel-src-tree
           fi
 
       - name: Build the Kernel