Add maintainer nomination template

This is a PR template to propose adding new maintainers

Fixes #912

Signed-off-by: nisha <[email protected]>

Author: nishakm

.github/PULL_REQUEST_TEMPLATE/maintainer_nomination.md

@@ -0,0 +1,21 @@
+# Nomination for a New Maintainer
+
+## Nominating Maintainer
+
+Name of the existing OCI maintainer with GitHub username
+
+## New Maintainer
+
+Name of the new maintainer with GitHub username
+
+## Justification
+
+Highlight any work contributed by the new maintainer. Examples of contributions may be:
+- Community involvement in mailing lists and meetings
+- Involvement in any OCI working groups
+- Contributions to any of the OCI git repositories
+
+Other considerations may be:
+- Diversity of organizations
+- Time involved in the community
+- Personal experience working with the new maintainer