docs: add link to PyPI (#10)

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Fixes #<issue_number_goes_here> 🦕

packages/googleapis-common-protos/README.md

@@ -1,7 +1,8 @@
 
 # Google APIs common protos
 
-TOOD: Add standard badges 
+[![pypi](https://img.shields.io/pypi/v/googleapis-common-protos.svg)](https://pypi.org/project/googleapis-common-protos/)
+
 
 googleapis-common-protos contains the python classes generated from the common
-protos in the [googleapis/api-common-protos](https://github.com/googleapis/api-common-protos) repository.
+protos in the [googleapis/api-common-protos](https://github.com/googleapis/api-common-protos) repository.