correct Repository.stargazers_count return type to int (#1513)

It appears this was a type annotation typo, as the type of the stargazers_count property has been int for a long time.

Author: scivision

github/Repository.pyi

@@ -474,7 +474,7 @@ class Repository(CompletableGithubObject):
     @property
     def ssh_url(self) -> str: ...
     @property
-    def stargazers_count(self) -> str: ...
+    def stargazers_count(self) -> int: ...
     @property
     def stargazers_url(self) -> str: ...
     @property