Added whatsnew documentation

Author: Connor

docs/sphinx/source/whatsnew/v0.10.0.rst

@@ -21,7 +21,7 @@ Deprecations
 
 Enhancements
 ~~~~~~~~~~~~
-
+* Added .pan/.ond reader function :py:func:'pvlib.iotools.panond'
 
 Bug fixes
 ~~~~~~~~~
@@ -45,3 +45,4 @@ Requirements
 Contributors
 ~~~~~~~~~~~~
 * Taos Transue (:ghuser:`reepoi`)
+* Connor Krening (:ghuser:'ckrening')