Build in separate step

Author: SimplyDanny

.github/workflows/test.yml

@@ -32,6 +32,7 @@ jobs:
         working-directory: ./SwiftLintPluginsTest
       - name: Build project and check findings
         run: |
+            swift build
             swift build 2>&1 | grep -q "Force Cast Violation"
         working-directory: ./SwiftLintPluginsTest
       - name: Verify command plugin