Try to set the working dir

Signed-off-by: Andreas Kern <[email protected]>

.github/workflows/filename-check.yml

@@ -5,6 +5,10 @@ on: [push]
 jobs:
   check-filenames:
     runs-on: ubuntu-latest
+    defaults:
+      run:
+        shell: bash
+        working-directory: .    
     steps:
     - uses: actions/checkout@v4
     - name: Check for capital letters in filenames in 'doc/manual'