Document renovate-bot breaking changes

In 1.49.0 a breaking change was introduced in the renovate-bot template breaking downstream projects that did not already had a `validate` stage.

This merge request documents the new requirements for the renovate-bot template inclusion

renovate-bot.md

@@ -2,7 +2,7 @@
 Runs [`renovatebot`](https://docs.renovatebot.com/) against the project to automatically upgrade dependencies.
-1. Ensure that a `renovate_bot` stage exists in your `.gitlab-ci.yml` configuration
+1. Ensure that a `validate` and `renovate_bot` stages exists in your `.gitlab-ci.yml` configuration
 1. Create a [Project Access Token](https://docs.gitlab.com/ee/user/project/settings/project_access_tokens.html) with `api` and `write_repository` scope and make it available in your CI environment via the `RENOVATE_GITLAB_TOKEN` environment variable through the CI/CD Variables settings. Make sure the variable is **Protected** and **Masked**.
 1. Lookup the GitHub Personal Access token from [1Password Production Vault](https://gitlab.1password.com/vaults/7xbs54owvjux3cypztlhyetej4/allitems/53z2zuf7urh7hoy3nqeqsei27e) and save it into the CI environment variable `RENOVATE_GITHUB_TOKEN`. Make sure the variable is **Protected** and **Masked**.
 1. Note that you can use Group Access Tokens and Group CI/CD variables, instead of Project-level ones should you choose.
@@ -19,6 +19,7 @@ Runs [`renovatebot`](https://docs.renovatebot.com/) against the project to autom
 ```yaml
 stages:
+  - validate
   - renovate_bot
 include: