Deprecate method get_ipv6_addr_by_EUI64

Oslo.utils provides same method get_ipv6_addr_by_EUI64,
so deprecate it in Newton and remove it in Ocata.

Co-Authored-By: guo yunxian <yunxian.guo@easystack.cn>

Change-Id: Ia72f866cda69b4f98e88936df32c76e455619d07
diff --git a/releasenotes/notes/deprecate-get_ipv6_addr_by_EUI64-4673f07677289cf6.yaml b/releasenotes/notes/deprecate-get_ipv6_addr_by_EUI64-4673f07677289cf6.yaml
new file mode 100644
index 0000000..0884cfa
--- /dev/null
+++ b/releasenotes/notes/deprecate-get_ipv6_addr_by_EUI64-4673f07677289cf6.yaml
@@ -0,0 +1,4 @@
+---
+deprecations:
+  - Oslo.utils provides same method get_ipv6_addr_by_EUI64,
+    so deprecate it in Newton and remove it in Ocata.