Add release policy (#362)

* Add release policy

* Update release_policy.md

Co-authored-by: Julia Sloan <[email protected]>

* Update release_policy.md

Co-authored-by: Julia Sloan <[email protected]>

---------

Co-authored-by: Julia Sloan <[email protected]>

Author: charleskawczynski

release_policy.md

@@ -0,0 +1,13 @@
+# Release policy
+
+ClimaTimesteppers.jl is a core component to the CliMA ecosystem, and can have
+a significant impact on users since most experiments and examples rely on this
+infrastructure.
+
+As such, we decided to enforce a release policy:
+
+Before making breaking releases, a stable patch release must be exercised by
+user repos and without new issues for at lease one week.
+
+This will help users to avoid issues when making updates, and developers to avoid the
+need to create patch releases along old minor versions.