update codecov action to v2

Author: patinthehat

.github/workflows/run-tests.yml

@@ -37,7 +37,7 @@ jobs:
         run: ./vendor/bin/phpunit --coverage-clover clover.xml -d --without-creating-snapshots
 
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@v1
+        uses: codecov/codecov-action@v2
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           files: clover.xml