Change runs-on tag in workflow

Author: michaelbutleridt

.github/workflows/tests.yml

@@ -5,7 +5,7 @@ on: [push, pull_request]
 jobs:
     tests:
         name: Tests PHP ${{ matrix.php }}
-        runs-on: ubuntu-latest
+        runs-on: nothing
         continue-on-error: ${{ matrix.experimental }}
         strategy:
             fail-fast: false