Include license file in the generated wheel package

The wheel package format supports including the license file. This is
done using the [metadata] section in the setup.cfg file. For additional
information on this feature, see:

https://wheel.readthedocs.io/en/stable/index.html#including-the-license-in-the-generated-wheel-file

Helps project comply with its own license:

> The above copyright notice and this permission notice shall be
> included in all copies or substantial portions of the Software.

1 files changed, 3 insertions, 0 deletions

diff --git a/setup.cfg b/setup.cfg
index 7c964b4..15d7017 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,2 +1,5 @@
 [wheel]
 universal=1
+
+[metadata]
+license_file = LICENSE.txt