Increase ccache hit rate by introducing sloppiness

.github/workflows/main.yaml

@@ -151,6 +151,7 @@ jobs:
           ccache --set-config=max_size=500M
           ccache --set-config=cache_dir=${{github.workspace}}/.ccache
           ccache --set-config=compression=true
+          ccache --set-config=sloppiness=include_file_mtime,include_file_ctime
           echo CCache config:
           ccache -p
           echo Clearing ccache statistics