Update most URLs to docs.github.com (#1896)

Now that GitHub have moved their documentation from
developer.github.com, we should update our links. I have also tried to
update the call strings to their new format, but since it was done via
regex, some of them may not match exactly.

github/RepositoryKey.py

@@ -38,7 +38,7 @@ import github.GithubObject
 
 class RepositoryKey(github.GithubObject.CompletableGithubObject):
     """
-    This class represents RepositoryKeys. The reference can be found here http://developer.github.com/v3/repos/#deploy-keys
+    This class represents RepositoryKeys. The reference can be found here http://docs.github.com/en/rest/reference/repos#deploy-keys
     """
 
     def __repr__(self):
@@ -102,7 +102,7 @@ class RepositoryKey(github.GithubObject.CompletableGithubObject):
 
     def delete(self):
         """
-        :calls: `DELETE /repos/:owner/:repo/keys/:id <http://developer.github.com/v3/repos/#deploy-keys>`_
+        :calls: `DELETE /repos/{owner}/{repo}/keys/{id} <http://docs.github.com/en/rest/reference/repos#deploy-keys>`_
         :rtype: None
         """
         headers, data = self._requester.requestJsonAndCheck("DELETE", self.url)