update knative-update-release.yaml (#173)

add note about closing&re-opening the PR to run the tests since the PR is created by the bot

Author: gauron99

.github/workflows/knative-update-release.yaml

@@ -27,4 +27,5 @@ jobs:
           commit-message: "Update kn formula to new version"
           delete-branch: true
           body: |
-            Generated by `./hack/update-taps.sh` to update formulas for a new release. 
+            Generated by `./hack/update-taps.sh` to update formulas for a new release.
+            Note: You might need to close & re-open this PR to run the tests.