chore: Move demo upgrade issue template (#665)

Author: Techassi

.github/ISSUE_TEMPLATE/pre-release-demos-nightly.md

@@ -44,7 +44,8 @@ Replace the items in the task lists below with the applicable Pull Requests / Is
 ### Pre-release
 - [ ] Run all of the test suites in Jenkins (with all product versions, not just "nightly")
 - [ ] [Check and update getting-started script](https://github.com/stackabletech/issues/issues/new?template=pre-release-getting-started-scripts.md)
-- [ ] [Test and update demos stable to nightly](https://github.com/stackabletech/issues/issues/new?template=pre-release-demos-nightly.md)
+- [ ] [Check and update demo charts](https://github.com/stackabletech/demos/issues/new?template=pre-release-chart-updates.md)
+- [ ] [Test and update demos stable to nightly](https://github.com/stackabletech/demos/issues/new?template=pre-release-nightly-testing.md)
 - [ ] Ensure integration tests are successful on OpenShift
 - [ ] Check stackable-utils scripts in dry-run mode work
 ```