chore(deps): update codecov/codecov-action action to v6

Author: renovate[bot]

.github/workflows/php-ci.yaml

@@ -95,7 +95,7 @@ jobs:
         composer run dev:test:integration:teardown
 
     - name: Upload coverage to Codecov
-      uses: codecov/codecov-action@v3
+      uses: codecov/codecov-action@v6
 
   ### TODO: Replicate any necessary package checks
   # packages: