Updated README.rst to cite the sources of work.

Cited sources of work for the project.

Author: wafels

README.rst

@@ -11,3 +11,5 @@ Helioviewer Python API Wrapper
 ``hvpy`` is a Python API wrapper around the formal `Helioviewer API <https://api.helioviewer.org/docs/v2/>`__.
 
 `Python API documentation <https://hvpy.readthedocs.io/en/latest/>`__
+
+This work was supported by the `2022 Google Summer of Code <https://summerofcode.withgoogle.com/>`__, the `SunPy Project <https://sunpy.org>`__, and the `Helioviewer Project <https://github.com/Helioviewer-Project/>`__.