Start 8.1+ branch for new major.

Author: dereuromark

.github/workflows/ci.yml

@@ -63,7 +63,7 @@ jobs:
       - name: Setup PHP
         uses: shivammathur/setup-php@v2
         with:
-          php-version: '7.4'
+          php-version: '8.1'
           extensions: mbstring, intl
           coverage: none