fix(action): cache-key not correctly set

Author: socheatsok78

action.yml

@@ -19,14 +19,14 @@ inputs:
   cache-key:
     description: "An explicit key for restoring and saving the Flutter SDK to/from cache"
     required: false
-    default: flutter-action-setup-flutter-${{ runner.os }}-${{ inputs.version }}-${{ inputs.channel }}-${{ runner.arch }}
+    default: "flutter"
 runs:
   using: "composite"
   steps:
     - if: ${{ inputs.cache == 'true' }}
       uses: actions/cache@v3
       with:
         path: ${{ runner.tool_cache }}/flutter-${{ runner.os }}-${{ inputs.version }}-${{ runner.arch }}
-        key: ${{ inputs.cache-key }}
+        key: flutter-action-setup-flutter-${{ runner.os }}-${{ inputs.version }}-${{ inputs.channel }}-${{ runner.arch }}-${{ inputs.cache-key }}
     - run: $GITHUB_ACTION_PATH/setup.sh ${{ inputs.version }} ${{ inputs.channel }}
       shell: bash