fix: clang-tidy: git diff base...head

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: wdconinc

.github/workflows/linux-eic-shell.yml

@@ -76,7 +76,7 @@ jobs:
         with:
           platform-release: "eic_xl:nightly"
           run: |
-            git diff ${{ github.event.pull_request.head.sha }} ${{ github.event.pull_request.base.sha }} | clang-tidy-diff -p 1 -path build -quiet -export-fixes clang_tidy_fixes.yaml
+            git diff ${{ github.event.pull_request.base.sha }} ${{ github.event.pull_request.head.sha }} | clang-tidy-diff -p 1 -path build -quiet -export-fixes clang_tidy_fixes.yaml
       - name: Run clang-tidy on all files
         uses: eic/run-cvmfs-osg-eic-shell@main
         if: ${{ github.event_name == 'push' }}