docs: use markdown for readme file

README.md

@@ -1,10 +1,8 @@
 
-Tailbone
-========
+# Tailbone
 
 Tailbone is an extensible web application based on Rattail.  It provides a
 "back-office network environment" (BONE) for use in managing retail data.
 
-Please see Rattail's `home page`_ for more information.
-
-.. _home page: http://rattailproject.org/
+Please see Rattail's [home page](http://rattailproject.org/) for more
+information.

pyproject.toml

@@ -8,7 +8,7 @@ build-backend = "hatchling.build"
 name = "Tailbone"
 version = "0.21.9"
 description = "Backoffice Web Application for Rattail"
-readme = "README.rst"
+readme = "README.md"
 authors = [{name = "Lance Edgar", email = "lance@edbob.org"}]
 license = {text = "GNU GPL v3+"}
 classifiers = [