Use the 'branch' auto merge type in renovate's configuration.

Instead of crating MRs, renovate will:

- Create the branch, wait for test results
- Rebase it any time it gets out of date with the base branch
- Automerge the branch commit if it's:
    (a) up-to-date with the base branch, and
    (b) passing all tests
- As a backup, raise a PR only if either:
    (a) tests fail, or
    (b) tests remain pending for too long (default: 24 hours)

Resolves #62

Signed-off-by: Miguel Martín <mmartinv@redhat.com>

renovate.json

@@ -4,6 +4,7 @@
     "github>platform-engineering-org/.github"
   ],
   "dependencyDashboard": true,
+  "automergeType": "branch",
   "tekton": {
     "additionalBranchPrefix": "",
     "includePaths": [