add evalaution to conditional expression

Author: LongLiveCHIEF

.github/workflows/build.yml

@@ -28,7 +28,7 @@ jobs:
   docker_build:
     runs-on: ubuntu-latest
     needs: filters
-    if: ${{ needs.filters.outputs.found_main_changes }}
+    if: ${{ needs.filters.outputs.found_main_changes == 'true' }}
 
     steps:
       - uses: actions/checkout@v2