Remove broken buildbot links in README badge line

It does not appear like the buildbot at ci.gnuradio.org is avialable
anymore. The README.md rendering looks odd with broken image and links.

Therefore I think we can just remove it as I think buildbot has been
ditched a long time ago by now in favor of Github Actions.

This then adds the Github workflow status badge with a link to the
status page.

Signed-off-by: Nick Østergaard <oe.nick@gmail.com>
(cherry picked from commit eab2ea6102fd7c84c9fd507b983698aa187df83b)
Signed-off-by: Jeff Long <willcode4@gmail.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/README.md b/README.md
index 447265417..df8696f8d 100755
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
 <img src="https://github.com/gnuradio/gnuradio/blob/master/docs/gnuradio.png" width="75%" />
 </p>
 
-[![Build](https://shield.lwan.ws/img/p5UKbS/weekly_runner)](https://ci.gnuradio.org/buildbot/#/)
+[![Make Test](https://github.com/gnuradio/gnuradio/actions/workflows/make-test.yml/badge.svg?branch=master)](https://github.com/gnuradio/gnuradio/actions/workflows/make-test.yml)
 ![Version](https://img.shields.io/github/tag/gnuradio/gnuradio.svg)
 [![AUR](https://img.shields.io/github/license/gnuradio/gnuradio)](https://github.com/gnuradio/gnuradio/blob/master/COPYING)
 [![Docs](https://img.shields.io/badge/docs-doxygen-orange.svg)](https://www.gnuradio.org/doc/doxygen/)