Revert "Start running against PHP v8"

This reverts commit db11f51.

Author: ssfinney

.github/workflows/ci.yml

@@ -12,7 +12,7 @@ jobs:
     strategy:
       fail-fast: true
       matrix:
-        php: [7.2, 7.3, 7.4, 8.0]
+        php: [7.2, 7.3, 7.4]
         stability: [prefer-lowest, prefer-stable]
 
     name: PHP ${{ matrix.php }} - ${{ matrix.stability }}
@@ -40,4 +40,4 @@ jobs:
         run: vendor/bin/phpunit --coverage-clover=coverage.clover --verbose
 
       - name: Upload Code Coverage
-        run: wget https://scrutinizer-ci.com/ocular.phar && php ocular.phar code-coverage:upload --format=php-clover coverage.clover
+        run: wget https://scrutinizer-ci.com/ocular.phar && php ocular.phar code-coverage:upload --format=php-clover coverage.clover