update Manifest

Signed-off-by: Karol Gugala <kgugala@antmicro.com>

MANIFEST.in

diff --git a/MANIFEST.in b/MANIFEST.in
index 5575478..0d2d920 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -6,3 +6,4 @@
 
 include *.yapf
 include *.txt
+recursive-include v2x *.py