docs!: upgrade of API version for Tekton Pipelines to v1

Author: msvticket

release-notes/tekton-v1.md

@@ -0,0 +1,28 @@
+# Upgrade of API version for Tekton Pipelines to v1
+
+With this upgrade the API version of Tekton Pipeline resources (like pipeline runs) are updated from tekton.dev/v1beta1
+to tekton.dev/v1.
+
+## Potential problems with conversion
+
+In the Jenkins X cluster upgrade process any changes to custome resource definitions are done first. In this case 
+this will trigger the Kubernetes cluster to ask tekton-pipelines-webhook to convert existing tekton pipeline 
+resources in the cluster. At this time the tekton-pipelines-webhook deployment is the old version which include bugs 
+that can cause old pipeline runs to run again. This can cause confusion especially if a release pipeline for an aold 
+versio of an application is run again.
+
+The simplest way to avoid this is to manually delete existing pipeline runs before doing this upgrade. This can be 
+done by running 
+
+```
+kubectl delete piplinerun --all -namespace jx
+```
+
+## Existing pipelines in application repositories
+
+So far the supported API version of the pipelines in the .ligthouse directory of your application respositories have 
+been tekton.dev/v1beta1. From now on tekton.dev/v1 is also supported. Any pipelines with version tekton.dev/v1beta1 
+will be automatically converted to tekton.dev/v1 when read by lighthouse. After the Tekton Pipelines project remove 
+support for this conversion it will be removed from lighthouse as well. But before that tools to convert the 
+piplines in .lighthouse will be made available.
+