Upgrade Keptn

Upgrade from Keptn 0.11.x to Keptn 0.12.0

Step 1. To download and install the Keptn CLI for version 0.12.0, you can choose between:
- Automatic installation of the Keptn CLI (Linux and Mac):
  - The next command will download the 0.12.0 release from GitHub, unpack it, and move it to /usr/local/bin/keptn.
```
curl -sL https://get.keptn.sh | KEPTN_VERSION=0.12.0 bash
```
  - Verify that the installation has worked and that the version is correct by running:
```
keptn version
```
- Manual installation of the Keptn CLI:
  - Download the release for your platform from the GitHub
  - Unpack the binary and move it to a directory of your choice (e.g., /usr/local/bin/)
  - Verify that the installation has worked and that the version is correct by running:
```
keptn version
```
Step 2. To upgrade your Keptn installation from 0.11.x to 0.12.0, the Keptn CLI offers the command:
```
keptn upgrade
```
- Please verify that you are connected to the correct Kubernetes cluster before executing this command.
- If you encounter an issue of the CLI saying: Error: your current Keptn CLI context 'cluster' does not match current Kubeconfig ' when executing the above command, please set the config KubeContextCheck using:
```
keptn set config KubeContextCheck true
```
- If the CLI still complains about the context, please use the Helm approach to upgrade your cluster:
```
helm upgrade keptn keptn --install -n keptn --create-namespace --repo=https://charts.keptn.sh --version=0.12.0 --reuse-values --wait
```

⚠️ Step 3. If you are using the jmeter-service or helm-service, upgrade them to 0.12.0 using the following commands:

helm repo update
helm upgrade jmeter-service https://github.com/keptn/keptn/releases/download/0.12.0/jmeter-service-0.12.0.tgz -n keptn --create-namespace --wait --reuse-values
helm upgrade helm-service https://github.com/keptn/keptn/releases/download/0.12.0/helm-service-0.12.0.tgz -n keptn --create-namespace --wait --reuse-values