Add a SUPPORT.md file

This adresses another of the missing items in the GitHub community
standards panel, https://github.com/quantumlib/TypedUnits/community

Author: mhucka

SUPPORT.md

@@ -0,0 +1,22 @@
+# Support
+
+Thank you for your interest in this project! If you are experiencing problems
+or have questions, the following are some suggestions for how to get help.
+
+> [!NOTE]
+> Before participating in our community, please read our [code of
+> conduct](CODE_OF_CONDUCT.md). By interacting with this repository,
+> organization, or community, you agree to abide by its terms.
+
+## Report an issue or request a feature
+
+To report an issue or request a feature in TypedUnits, please first search the
+[issue tracker on GitHub](https://github.com/quantumlib/TypedUnits/issues) to
+check if there is already an open issue identical or similar to your bug
+report/feature request. If there is none, go ahead and file a new issue in the
+issue tracker.
+
+## Contact the maintainers
+
+For any questions or concerns not addressed here, please email
+[quantum-oss-maintainers@google.com](mailto:quantum-oss-maintainers@google.com).