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