add instrumentation approvers as per SIG governance

Change-Id: Ib7e8ef3d5932c4f6fb93397702b25160c851e3ad

Author: Han Kang

OWNERS_ALIASES

@@ -307,8 +307,11 @@ aliases:
     - MaciekPytel
     - mwielgus
   sig-instrumentation-approvers:
-    - piosz
     - brancz
+    - logicalhan
+    - dashpole
+    - ehashman
+    - RainbowMango
     - serathius
   sig-instrumentation-reviewers:
     - kawych