chore: Update issue template for demo upgrade tests (#377)

Author: sbernauer

.github/ISSUE_TEMPLATE/pre-release-upgrade-testing.md

@@ -113,20 +113,14 @@ stackablectl stack install <STACK_NAME>
 # --- IMPORTANT ---
 # Run through the (still) nightly demo/stack instructions (refer to the list above).
 
-# Get a list of installed operators
-stackablectl operator installed --output=plain
+# Install nightly version of operators
+stackablectl release upgrade dev
 
-# Uninstall operators for the stable release (OO.M)
-stackablectl release uninstall OO.M
-
-# Update CRDs to nightly version (on main)
-# Repeat this for every operator used by the demo (use the list from the earlier step before deleting the operators)
-kubectl replace -f https://raw.githubusercontent.com/stackabletech/commons-operator/main/deploy/helm/commons-operator/crds/crds.yaml
-kubectl replace -f https://raw.githubusercontent.com/stackabletech/...-operator/main/deploy/helm/...-operator/crds/crds.yaml
+# Bump every stacklet to the version that used by the nightly demo.
+# Typically, this is the latest supported version.
+kubectl patch hbaseclusters/hbase --type='json' -p='[{"op": "replace", "path": "/spec/image/productVersion", "value":"x.x.x"}]' # changed
 
-# Install nightly version of operators (use the list from the earlier step before deleting the operators)
-stackablectl operator install commons ...
+# Check that the operator logs look good (no unexpected errors etc.)
 
-# Optionally update the product versions in the CRDs (to the latest non-experimental version for the new release), e.g.:
-kubectl patch hbaseclusters/hbase --type='json' -p='[{"op": "replace", "path": "/spec/image/productVersion", "value":"x.x.x"}]' # changed
+# Run through the (still) nightly demo/stack instructions again.
 ```