Update workflow to use maximize-kselftest-coverage branch

Author: shreeya-patel98

.github/workflows/kernel-build-and-test-x86_64.yml

@@ -22,7 +22,7 @@ jobs:
       uses: actions/checkout@v4
       with:
         repository: ctrliq/kernel-container-build
-        ref: test-stage-separation
+        ref: maximize-kselftest-coverage
         path: kernel-container-build
         token: ${{ secrets.PRIVATE_REPO_ACCESS_TOKEN }}
 
@@ -92,7 +92,7 @@ jobs:
       uses: actions/checkout@v4
       with:
         repository: ctrliq/kernel-container-build
-        ref: test-stage-separation
+        ref: maximize-kselftest-coverage
         path: kernel-container-build
         token: ${{ secrets.PRIVATE_REPO_ACCESS_TOKEN }}
 
@@ -146,7 +146,7 @@ jobs:
       uses: actions/checkout@v4
       with:
         repository: ctrliq/kernel-container-build
-        ref: test-stage-separation
+        ref: maximize-kselftest-coverage
         path: kernel-container-build
         token: ${{ secrets.PRIVATE_REPO_ACCESS_TOKEN }}