Update main.yml (EbookFoundation#5203)

Author: borgified

.github/workflows/main.yml

@@ -5,7 +5,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v1
-      - uses: trilom/[email protected].3
+      - uses: trilom/[email protected].4
         id: file_changes
         with:
           output: ''