chore(bazel): update Python gapic generator

Google APIs · copybara-github · commit d419a199887c · 2023-03-15T11:02:33.000-07:00
PiperOrigin-RevId: 516873747
diff --git a/WORKSPACE b/WORKSPACE
@@ -318,7 +318,7 @@ load("@rules_python//python:pip.bzl", "pip_install")
 
 pip_install()
 
-_gapic_generator_python_version = "1.8.5"
+_gapic_generator_python_version = "1.8.6"
 
 http_archive(
     name = "gapic_generator_python",
