Fix appveyor badge (wrong account), and also show main build rather t…

…han latest.

README.rst

@@ -19,7 +19,7 @@ official releases, installation instructions, documentation, and examples.
 .. |LinuxTests| image:: https://travis-ci.org/holoviz/param.svg?branch=master
 .. _LinuxTests: https://travis-ci.org/holoviz/param
 
-.. |WinTests| image:: https://ci.appveyor.com/api/projects/status/1p5aom8o0tfgok1r?svg=true
+.. |WinTests| image:: https://ci.appveyor.com/api/projects/status/jv1j2036g0a5t5qx/branch/master?svg=true
 .. _WinTests: https://ci.appveyor.com/project/holoviz-developers/param/branch/master
 
 .. |Coverage| image:: https://coveralls.io/repos/github/holoviz/param/badge.svg?branch=master