Added tips on releasing client and checking with k8s. (#1723)

Signed-off-by: bwplotka <[email protected]>

Author: bwplotka

RELEASE.md

@@ -61,6 +61,16 @@ We use [Semantic Versioning](https://semver.org/).
    - Click "Publish release"!
    - Create PR against [prometheus/prometheus](https://github.com/prometheus/prometheus) using RC version (e.g. https://github.com/prometheus/prometheus/pull/15851)
    - Create PR against [kubernetes/kubernetes](https://github.com/kubernetes/kubernetes) using RC version (e.g. https://github.com/kubernetes/kubernetes/pull/129752)
+     - Kubernetes uses scripts to update deps  e.g.: 
+ 
+```bash
+./hack/pin-dependency.sh github.com/prometheus/client_golang v1.21.0-rc.0
+./hack/update-vendor.sh
+# If indirect dependencies changed, following check will fail on the CI:
+./hack/verify-vendor.sh
+# You will need to modify hack/unwanted-dependencies.json manually as the check suggests.
+```
+     
    - Make sure the CI is green for the PRs
    - Allow 1-2 days for downstream testing
    - Fix any issues found before final release