docs: fix badges in README (#22)

* docs: fix targets in README

* docs: also fix the badge image link

* docs: one more

Author: busunkim96

README.rst

@@ -12,12 +12,12 @@ plan.
 
 .. |beta| image:: https://img.shields.io/badge/support-beta-orange.svg
    :target: https://github.com/googleapis/google-cloud-python/blob/master/README.rst#beta-support
-.. |pypi| image:: https://img.shields.io/pypi/v/google-cloud-billingbudgets.svg
-   :target: https://pypi.org/project/google-cloud-billingbudgets
-.. |versions| image:: https://img.shields.io/pypi/pyversions/google-cloud-billingbudgets.svg
-   :target: https://pypi.org/project/google-cloud-billingbudgets/
+.. |pypi| image:: https://img.shields.io/pypi/v/google-cloud-billing-budgets.svg
+   :target: https://pypi.org/project/google-cloud-billing-budgets
+.. |versions| image:: https://img.shields.io/pypi/pyversions/google-cloud-billing-budgets.svg
+   :target: https://pypi.org/project/google-cloud-billing-budgets/
 .. _Cloud Billing Budget API: https://cloud.google.com/billing/docs/how-to/budget-api-overview
-.. _Client Library Documentation: https://googleapis.dev/python/billingbudgets/latest
+.. _Client Library Documentation: https://googleapis.dev/python/billing-budgets/latest
 .. _Product Documentation:  https://cloud.google.com/billing/docs/how-to/budget-api-overview
 
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