Make _create_security_group_rule non-private

_create_security_group_rule() is currently private
which is not necessarily required to be private

Implements: blueprint tempest-scenario-manager-stable
Signed-off by: Soniya Vyas<svyas@redhat.com>

Change-Id: I0e8800d20e3cbb0d8290e4a1372a2ba543288d17
diff --git a/releasenotes/notes/create_security_group_rule-16d58a8f0f0ff262.yaml b/releasenotes/notes/create_security_group_rule-16d58a8f0f0ff262.yaml
new file mode 100644
index 0000000..3354f65
--- /dev/null
+++ b/releasenotes/notes/create_security_group_rule-16d58a8f0f0ff262.yaml
@@ -0,0 +1,6 @@
+---
+features:
+  - |
+    Added public interface create_security_group_rule().
+    Since this interface is meant to be used by tempest plugins,
+    It doesn't neccessarily require to be private api.