chore(deps): update dependency google-api-core to v1.20.1 (#463)

Author: renovate-bot

requirements.txt

@@ -1,5 +1,5 @@
 click==7.1.2
-google-api-core==1.20.0
+google-api-core==1.20.1
 googleapis-common-protos==1.52.0
 jinja2==2.11.2
 MarkupSafe==1.1.1