feat: added check_username function

mojang/api/session.py

@@ -44,6 +44,18 @@ def check_product_voucher(access_token: str, voucher: str) -> bool:
     return code == 200
 
 
+def check_username(access_token: str, username: str) -> bool:
+    headers = helpers.get_headers(bearer=access_token)
+    response = requests.get(
+        urls.api_session_check_username(username), headers=headers
+    )
+    code, data = helpers.err_check(
+        response, (401, Unauthorized), (429, RuntimeError("Limited Endpoint"))
+    )
+
+    return data["status"] == "AVAILABLE"
+
+
 def get_user_name_change(access_token: str) -> NameChange:
     """Return if user can change name and when it was created