Merge branch 'update-readme' into 'master'

Add slack workspace, update the summary info, and add conda forge badge

See merge request !342

README.rst

-|pipeline status| |coverage report| |pypi| |version|
+|pipeline status| |coverage report| |pypi| |conda| |version|
 
 Bilby
 =====
 
-Fulfilling all your Bayesian inference dreams.
+A user-friendly Bayesian inference library.
+Fulfilling all your Bayesian dreams.
 
 -  `Installation
    instructions <https://lscsoft.docs.ligo.org/bilby/installation.html>`__
 -  `Contributing <https://git.ligo.org/lscsoft/bilby/blob/master/CONTRIBUTING.md>`__
 -  `Documentation <https://lscsoft.docs.ligo.org/bilby/index.html>`__
 -  `Issue tracker <https://git.ligo.org/lscsoft/bilby/issues>`__
+-  `Slack workspace <https://bilby-code.slack.com/>`__
 
 We encourage you to contribute to the development via a merge request.  For
 help in creating a merge request, see `this page
@@ -22,5 +24,7 @@ us directly.
    :target: https://lscsoft.docs.ligo.org/bilby/htmlcov/
 .. |pypi| image:: https://badge.fury.io/py/bilby.svg
    :target: https://pypi.org/project/bilby/
+.. |conda| image:: https://img.shields.io/conda/vn/conda-forge/bilby.svg
+   :target: https://anaconda.org/conda-forge/bilby
 .. |version| image:: https://img.shields.io/pypi/pyversions/bilby.svg
    :target: https://pypi.org/project/bilby/