exclude known-bad combinations

Author: jwong-dayspring

.github/workflows/ci.yml

@@ -23,6 +23,16 @@ jobs:
           - '6.2.*'
           - '6.3.*'
           - '6.4.*'
+        exclude:
+          # symfony 6.1+ requires PHP 8.1+
+          - php: '8.0'
+            symfony_version: '6.1.*'
+          - php: '8.0'
+            symfony_version: '6.2.*'
+          - php: '8.0'
+            symfony_version: '6.3.*'
+          - php: '8.0'
+            symfony_version: '6.4.*'
 #        deps:
 #          - 'highest'
 #          - 'lowest'