[ci] Configure renovate per branch (#522)

(cherry picked from commit f9fd0b1)

Author: jsanz

.backportrc.json

@@ -3,6 +3,11 @@
   "repoName": "ems-file-service",
   "targetBranches": ["feature-layers"],
   "targetPRLabels": ["backport"],
+  "branchLabelMapping": {
+    "feature-layers": "feature-layers"
+  },
+  "autoMerge": false,
+  "autoMergeMethod": "squash",
   "commitConflicts": true,
   "fork": false
 }

renovate.json

@@ -4,5 +4,9 @@
   "minimumReleaseAge": "14 days",
   "extends": [
     "github>elastic/renovate-config"
+  ],
+  "baseBranches": ["master", "feature-layers"],
+  "labels": [
+    "dependencies"
   ]
 }