VOL-2623 adding update_flows_incrementally support to onu-adapter
With this task queuing of vlan_filter task is done per tp_id and
the signature of the constructor of vlan_filter task is changed to include default_vlan and vlan_pcp.

Change-Id: Ib83f0362cb5923f88d98f25c02241dd3d2019e0c
diff --git a/python/requirements.txt b/python/requirements.txt
index daf3dd8..85c6640 100644
--- a/python/requirements.txt
+++ b/python/requirements.txt
@@ -1,2 +1,2 @@
 voltha-protos==3.2.3
-pyvoltha==2.3.14
+pyvoltha==2.3.15