Revert PHP8 test change

Author: canvural

.github/workflows/tests.yml

@@ -69,7 +69,7 @@ jobs:
 
     strategy:
       matrix:
-        php: [7.4, 8.0]
+        php: [7.4]
 
         dependencies: [locked]
 
@@ -127,7 +127,7 @@ jobs:
 
     strategy:
       matrix:
-        php: [7.4, 8.0]
+        php: [7.4]
 
         dependencies:
           - "lowest"