Replace Qt 5 with Qt 6

Author: TheAssassin

.github/workflows/main.yml

@@ -11,7 +11,7 @@ jobs:
     - uses: actions/checkout@v2
 
     - name: Install dependencies
-      run: sudo apt-get install -y libgrantlee5-dev qt5-default qtdeclarative5-dev-tools
+      run: sudo apt-get install -y libgrantlee5-dev qt6-base-dev qt6-base-dev-tools qt6-declarative-dev qt6-declarative-dev-tools
 
     - name: Lint test script
       run: shellcheck ./tests/test-plugins.sh