Updating to latest openolt chart after release

Change-Id: Ie1e26ed40ee9af787cb42d32ab989eb7515c154c
diff --git a/git_refs b/git_refs
index f9840b5..08b04c4 100644
--- a/git_refs
+++ b/git_refs
@@ -11,17 +11,15 @@
 
 _REPO NAME_             _DIR_    _REF_
 
-bbsim                        /        master
-cord-tester                  /        master
-ofagent-go                   /        master
-openolt                      /        master
-pyvoltha                     /        master
-voltctl                      /        master
-voltha-go                    /        master
-voltha-openolt-adapter       /        master
-voltha-openonu-adapter       /        master
-voltha-openonu-adapter-go    /        master
-voltha-protos                /        master
-voltha-system-tests          /        master
-device-management-interface  /        master
-voltha-helm-charts           /        master
+bbsim                        /        a9875ddcbaf846e970826004db51f9a15a465911
+cord-tester                  /        44ef9be3bf8f18fd64ea8cf44b5171ca049b9ef9
+ofagent-go                   /        voltha-2.8
+openolt                      /        voltha-2.8
+voltctl                      /        voltha-2.8
+voltha-go                    /        voltha-2.8
+voltha-openolt-adapter       /        voltha-2.8
+voltha-openonu-adapter-go    /        voltha-2.8
+voltha-protos                /        9c3e1c8dc6a867d0f552861d2b36d0b44ca68fb1
+voltha-system-tests          /        voltha-2.8
+device-management-interface  /        6bdb0f7eb9f3bca1842d01bb55625fafd70279fc
+voltha-helm-charts           /        voltha-2.8