Use Xdebug instead of PCOV to work around #4622

Author: sebastianbergmann

.github/workflows/ci.yml

@@ -125,7 +125,7 @@ jobs:
         uses: shivammathur/setup-php@v2
         with:
           php-version: ${{ matrix.php-version }}
-          coverage: pcov
+          coverage: xdebug
           extensions: dom, json, libxml, mbstring, pdo_sqlite, soap, xml, xmlwriter
           ini-values: assert.exception=1, zend.assertions=1