Revert "Bump subosito/flutter-action from 2.19.0 to 2.20.0 (#121)"

This reverts commit 532b307.

Author: domesticmouse

.github/workflows/main.yml

@@ -32,7 +32,7 @@ jobs:
         with:
           distribution: 'zulu'
           java-version: '17'
-      - uses: subosito/flutter-action@395322a6cded4e9ed503aebd4cc1965625f8e59a
+      - uses: subosito/flutter-action@e938fdf56512cc96ef2f93601a5a40bde3801046
         with:
           channel: ${{ matrix.flutter_version }}
       - run: ./flutter_ci_script_${{ matrix.flutter_version }}.sh