Add PHP 7.3 to tests

Author: e1himself

.github/workflows/test.yml

@@ -6,7 +6,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        php: ['7.4', '8.0', '8.1']
+        php: ['7.3', '7.4', '8.0', '8.1']
 
     steps:
       - uses: actions/checkout@master