Add badges (#354)

Author: jarrodmillman

README.rst

@@ -1,12 +1,17 @@
-.. |docs| image:: https://readthedocs.org/projects/numpydoc/badge/?version=latest
+=====================================
+numpydoc -- Numpy's Sphinx extensions
+=====================================
+
+.. image:: https://readthedocs.org/projects/numpydoc/badge/?version=latest
    :alt: Documentation Status
    :scale: 100%
-   :target: https://numpydoc.readthedocs.io/en/latest/?badge=latest
+   :target: https://numpydoc.readthedocs.io/en/latest/
 
+.. image:: https://codecov.io/gh/numpy/numpydoc/branch/main/graph/badge.svg
+   :target: https://app.codecov.io/gh/numpy/numpydoc/branch/main
 
-=====================================
-numpydoc -- Numpy's Sphinx extensions
-=====================================
+.. image:: https://github.com/numpy/numpydoc/actions/workflows/test.yml/badge.svg?branch=main
+   :target: https://github.com/numpy/numpydoc/actions/workflows/test.yml
 
 This package provides the ``numpydoc`` Sphinx extension for handling
 docstrings formatted according to the NumPy documentation format.