gclient: update logging.warn to logging.warning.

logging.warn is deprecated.

Change-Id: I047f356b8eeced631edc51e3b846f0995f4ce95e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/2124526Reviewed-by: Edward Lesmes <ehmaldonado@chromium.org>
Commit-Queue: John Budorick <jbudorick@chromium.org>

gclient.py

@@ -601,7 +601,7 @@ class Dependency(gclient_utils.WorkItem, DependencySettings):
               self.url))
       # In theory we could keep it as a shadow of the other one. In
       # practice, simply ignore it.
-      logging.warn('Won\'t process duplicate dependency %s' % sibling)
+      logging.warning("Won't process duplicate dependency %s" % sibling)
       return False
     return True
 

gclient_scm.py

@@ -885,8 +885,8 @@ class GitWrapper(SCMWrapper):
     except NoUsableRevError as e:
       # If the DEPS entry's url and hash changed, try to update the origin.
       # See also http://crbug.com/520067.
-      logging.warn(
-          'Couldn\'t find usable revision, will retrying to update instead: %s',
+      logging.warning(
+          "Couldn't find usable revision, will retrying to update instead: %s",
           e.message)
       return self.update(options, [], file_list)