Remove 7.3.3 from tests (composer error)

Author: randoum

.github/workflows/unittest.yml

@@ -8,7 +8,7 @@ jobs:
     strategy:
       matrix:
         operating-system: [ ubuntu-18.04, windows-2016 ]
-        php: [ '7.1', '7.2', '7.3', '7.4', '7.3.3' ]
+        php: [ '7.1', '7.2', '7.3', '7.4' ]
 
     env:
       EMAIL_VALIDATION_API_KEY: ${{ secrets.API_KEY }}