chore: use gapic-generator-python 0.50.3

Google APIs · copybara-github · commit 513440fda515 · 2021-06-29T12:39:00.000-07:00
fix: disable always_use_jwt_access Committer: @busunkim96 PiperOrigin-RevId: 382142900
diff --git a/WORKSPACE b/WORKSPACE
@@ -224,7 +224,7 @@ load("@rules_python//python:pip.bzl", "pip_repositories")
 
 pip_repositories()
 
-_gapic_generator_python_version = "0.50.2"
+_gapic_generator_python_version = "0.50.3"
 
 http_archive(
     name = "gapic_generator_python",
