docs: publish our release maintainers' keys

They should be published to various key servers as well, but this
provides the authoritative source for their list.

Closes: https://gitlab.freedesktop.org/mesa/mesa/issues/2140
Signed-off-by: Eric Engestrom <eric@engestrom.ch>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/2857>
diff --git a/docs/conf.py b/docs/conf.py
index 2c7f9c3..65bd4c9 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -114,6 +114,7 @@
 
 html_extra_path = [
   '_extra/',
+  'release-maintainers-keys/',
   'features.txt',
   'libGL.txt',
   'README.UVD',