add contributing guide under sig-auth

Author: pravarag

sig-auth/CONTRIBUTING.md

@@ -0,0 +1,62 @@
+# Contributing to SIG Auth
+
+Welcome to contributing to SIG Auth.
+
+If you haven't seen them already, the Kubernetes project has:
+
+- A [Contributor Guide][contrib-guide] - some
+  [kubernetes/kubernetes]-specific content, but lots of info for the
+  entire project
+- A [Contributor Cheat Sheet][contrib-cheatsheet] - lots of resources
+  and handy links
+
+SIG Auth has multiple areas you can contribute to. Those contributions
+can be in the form of code, documentation, support being involved in
+mailing list discussions, attending meetings, and more. This guide
+describes different major functional areas SIG Auth is involved in,
+provides an overview of the areas, and gives pointers on getting more
+involved in each area. Consider this a launching point or the start of
+a [choose your own
+adventure](https://en.wikipedia.org/wiki/Choose_Your_Own_Adventure)
+for SIG Auth.
+
+## Workflow
+
+Just like rest of the Kubernetes project, we also use the same PR and
+review based workflow. Which means [use of the CNCF CLA][cla], [code
+review by reviewers and approvers listed in OWNERS files][owners], and
+tests that automatically exercise code or enforce conventions.
+
+## Issue Triaging
+
+Issues are ideally labeled with:
+
+- milestone: during which release cycle do we plan on working on this issue
+- `sig/foo`: which SIG owns this work
+- `area/foo`: which subproject or code is this issue related to
+- `kind/foo`: which kind of work is this issue describing
+- `priority/foo`: how important is this issue
+
+For example, an issue related to cleaning up and consolidating
+(`kind/cleanup`) release-related (`sig/release`) jobs and dashboards
+(`area/config`) for the v1.16 cycle (`milestone: v1.16`) that may not
+get completed by the end of the cycle if more important or more urgent
+work arises (`priority/important-longterm`).
+
+We try to have a non-stale pool of issues that are available for new
+contributors who want to help out but aren't sure what to work on or where to
+get started:
+
+- [`label:"good first issue"`][good-first-issue] - triaged per
+  [good-first-issue](https://github.com/issues?q=repo%3Akubernetes%2Fkubernetes+is%3Aissue+is%3Aopen+label%3A%22good+first+issue%22+label%3A%22sig%2Fauth%22)
+- [good-first-issue-docs](https://git.k8s.io/community/contributors/guide/help-wanted.md#good-first-issue)
+- [`label:"help wanted"`][help-wanted] - triaged per
+  [help-wanted](https://github.com/issues?q=repo%3Akubernetes%2Fkubernetes+is%3Aissue+is%3Aopen+label%3A%22help+wanted%22++label%3A%22sig%2Fauth%22)
+- [help-wanted-docs](https://git.k8s.io/community/contributors/guide/help-wanted.md#help-wanted)
+  
+## Guides
+
+If you're not sure where to contribute or what any of these mean,
+please see
+[README.md](https://github.com/kubernetes/community/blob/master/README.md)
+for a brief description of the various codebases in this repo.