Typo usersername should be username (#63671)

##### SUMMARY
Typo in examples using api_username. Example incorrectly has usersername.


##### ISSUE TYPE
- Docs Pull Request

+label: docsite_pr

lib/ansible/modules/source_control/gitlab_group.py

@@ -97,7 +97,7 @@ EXAMPLES = '''
   gitlab_group:
     api_url: https://gitlab.example.com/
     validate_certs: True
-    api_usersername: dj-wasabi
+    api_username: dj-wasabi
     api_password: "MySecretPassword"
     name: my_first_group
     path: my_first_group
@@ -108,7 +108,7 @@ EXAMPLES = '''
   gitlab_group:
     api_url: https://gitlab.example.com/
     validate_certs: True
-    api_usersername: dj-wasabi
+    api_username: dj-wasabi
     api_password: "MySecretPassword"
     name: my_first_group
     path: my_first_group