Sync GithubIntegration __init__ arguments with github.Github (#2556)

Github and GithubIntegration now both support the same (full) set of Requester arguments.
Creating a Github instance for a Github App Installation coming from GithubIntegration uses the same
Requester arguments (except for auth).

github/GithubIntegration.py

@@ -1,7 +1,9 @@
 import warnings
 
 import deprecated
+import urllib3
 
+import github
 from github import Consts
 from github.Auth import AppAuth
 from github.GithubApp import GithubApp
@@ -17,6 +19,7 @@ class GithubIntegration:
     Main class to obtain tokens for a GitHub integration.
     """
 
+    # keep non-deprecated arguments in-sync with Requester
     # v2: remove integration_id, private_key, jwt_expiry, jwt_issued_at and jwt_algorithm
     # v2: move auth to the front of arguments
     # v2: add * before first argument so all arguments must be named,
@@ -26,6 +29,12 @@ class GithubIntegration:
         integration_id=None,
         private_key=None,
         base_url=Consts.DEFAULT_BASE_URL,
+        timeout=Consts.DEFAULT_TIMEOUT,
+        user_agent=Consts.DEFAULT_USER_AGENT,
+        per_page=Consts.DEFAULT_PER_PAGE,
+        verify=True,
+        retry=None,
+        pool_size=None,
         jwt_expiry=Consts.DEFAULT_JWT_EXPIRY,
         jwt_issued_at=Consts.DEFAULT_JWT_ISSUED_AT,
         jwt_algorithm=Consts.DEFAULT_JWT_ALGORITHM,
@@ -35,8 +44,15 @@ class GithubIntegration:
         :param integration_id: int deprecated, use auth=github.Auth.AppAuth(...) instead
         :param private_key: string deprecated, use auth=github.Auth.AppAuth(...) instead
         :param base_url: string
+        :param timeout: integer
+        :param user_agent: string
+        :param per_page: int
+        :param verify: boolean or string
+        :param retry: int or urllib3.util.retry.Retry object
+        :param pool_size: int
         :param jwt_expiry: int deprecated, use auth=github.Auth.AppAuth(...) instead
         :param jwt_issued_at: int deprecated, use auth=github.Auth.AppAuth(...) instead
+        :param jwt_algorithm: string deprecated, use auth=github.Auth.AppAuth(...) instead
         :param auth: authentication method
         """
         if integration_id is not None:
@@ -46,6 +62,16 @@ class GithubIntegration:
                 private_key, str
             ), "supplied private key should be a string"
         assert isinstance(base_url, str), base_url
+        assert isinstance(timeout, int), timeout
+        assert user_agent is None or isinstance(user_agent, str), user_agent
+        assert isinstance(per_page, int), per_page
+        assert isinstance(verify, (bool, str)), verify
+        assert (
+            retry is None
+            or isinstance(retry, int)
+            or isinstance(retry, urllib3.util.Retry)
+        ), retry
+        assert pool_size is None or isinstance(pool_size, int), pool_size
         assert isinstance(jwt_expiry, int), jwt_expiry
         assert Consts.MIN_JWT_EXPIRY <= jwt_expiry <= Consts.MAX_JWT_EXPIRY, jwt_expiry
         assert isinstance(jwt_issued_at, int)
@@ -81,14 +107,21 @@ class GithubIntegration:
         self.__requester = Requester(
             auth=auth,
             base_url=self.base_url,
-            timeout=Consts.DEFAULT_TIMEOUT,
-            user_agent="PyGithub/Python",
-            per_page=Consts.DEFAULT_PER_PAGE,
-            verify=True,
-            retry=None,
-            pool_size=None,
+            timeout=timeout,
+            user_agent=user_agent,
+            per_page=per_page,
+            verify=verify,
+            retry=retry,
+            pool_size=pool_size,
         )
 
+    def get_github_for_installation(self, installation_id):
+        # The installation has to authenticate as an installation, not an app
+        auth = self.auth.get_installation_auth(
+            installation_id, requester=self.__requester
+        )
+        return github.Github(**self.__requester.withAuth(auth).kwargs)
+
     def _get_headers(self):
         """
         Get headers for the requests.