chore: blacken (#206)

Also, fix 2.7 tests broken by release of 'googleapis-common-protos 1.53.0',
which dropped Python 2.7 support.

Closes #169
diff --git a/owlbot.py b/owlbot.py
index 2a525c8..5c590e4 100644
--- a/owlbot.py
+++ b/owlbot.py
@@ -14,8 +14,6 @@
 
 """This script is used to synthesize generated parts of this library."""
 
-import re
-
 import synthtool as s
 from synthtool import gcp
 
@@ -38,3 +36,5 @@
 .pytype
 """,
 )
+
+s.shell.run(["nox", "-s", "blacken"], hide_output=False)