chore: Add Chart update issue template

Author: Techassi

.github/ISSUE_TEMPLATE/pre-release-chart-updates.md

@@ -0,0 +1,57 @@
+---
+name: Pre-Release Demo Chart Updates
+about: This template can be used to track the Helm chart updates for all demos.
+title: "chore(tracking): Update Helm charts for XX.(X)X"
+labels: []
+assignees: ''
+---
+
+## Pre-Release Demo Chart Updates
+
+There are a bunch of demos which directly use Helm charts to install some required parts of the
+demo / stack. These charts need updating **before** we start testing the stable to nightly upgrade.
+
+Most of the charts are located in the `stacks/_templated` folder. Additional folders are:
+`stacks/observability` and `stacks/signal-processing`. It is recommended to search for `releaseName`
+to find all referenced charts.
+
+### Update Instructions
+
+These instructions help to update the charts:
+
+```shell
+# List all available repos
+helm repo list
+```
+
+Make sure, you have the following repos added:
+
+```plain
+NAME                  URL
+bitnami               https://charts.bitnami.com/bitnami
+stackable-dev         https://repo.stackable.tech/repository/helm-dev/
+stackable-stable      https://repo.stackable.tech/repository/helm-stable/
+timescale             https://charts.timescale.com/
+prometheus-community  https://prometheus-community.github.io/helm-charts
+vector                https://helm.vector.dev
+grafana               https://grafana.github.io/helm-charts
+jaeger                https://jaegertracing.github.io/helm-charts
+opentelemetry         https://open-telemetry.github.io/opentelemetry-helm-charts
+jupyterhub            https://jupyterhub.github.io/helm-chart/
+opensearch            https://opensearch-project.github.io/helm-charts
+```
+
+Next, search for the latest version of the desired chart, eg `grafana/grafana`:
+
+```shell
+# Display the latest versions of a chart
+$ helm search repo grafana/grafana --versions | head -5
+NAME             CHART VERSION  APP VERSION
+grafana/grafana  8.6.0          11.3.0
+grafana/grafana  8.5.12         11.3.0
+grafana/grafana  8.5.11         11.3.0
+grafana/grafana  8.5.10         11.3.0
+```
+
+Use the latest version displayed to replace the current one in the YAML files. Take a look at
+previous PRs for additional guidance, eg. <https://github.com/stackabletech/demos/pull/119>.