Add issue template for public release checklist

.github/ISSUE_TEMPLATE/owncast-release-checklist.md

@@ -0,0 +1,20 @@
+---
+name: Owncast release checklist
+about: A template with steps required for releasing a build of Owncast
+title: Owncast release 0.0.x
+labels: documentation, Testing
+assignees: gabek
+
+---
+
+## Owncast release 0.0.x
+
+The following are intended to address the test scenarios and documentation that should be accomplished for a public release.
+
+- [ ] This release was tested as a fresh install, with no pre-existing data or configuration.
+- [ ] This release was tested as an upgrade over a previous install, keeping the data and configuration.
+- [ ] This release was tested using a Docker environment.
+- [ ] Release notes and a changelog was written to call out the new features, changes to existing features, and user-impacting behind the scenes updates.
+- [ ] Upgrade instructions were written for migrating from the previous release.
+- [ ] The API spec `openapi.yaml` is up to date, and the current version of the release is specified in the file.
+- [ ] The API documentation was copied to the public documentation site under `/api`.