Correct extension typo

Owen Synge · Owen Synge · commit 56d9f93700dc · 2018-09-21T23:54:45.000+02:00
diff --git a/MANIFEST.in b/MANIFEST.in
@@ -1,3 +1,3 @@
-include README.rst
+include README.md
 include CHANGELOG.md
 include LICENSE
