Add renovate to repo (#3)

* Add renovate linting step
* Add renovate rules
    * Grouping major vs minor updates
    * Scheduling

.github/workflows/ci.yml

@@ -13,4 +13,13 @@ jobs:
         with:
           java-version: 1.8
       - name: Build
-        run: ./gradlew build
+        run: ./gradlew build
+
+  renovate:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: 🧼 lint renovate config # Validates changes to renovate.json config file
+        uses: suzuki-shunsuke/[email protected]
+        with:
+          config_file_path: 'renovate.json'

renovate.json

@@ -0,0 +1,40 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    "config:base",
+    ":rebaseStalePrs",
+    "schedule:weekly"
+  ],
+  "enabledManagers": [
+    "github-actions",
+    "gradle",
+    "gradle-wrapper"
+  ],
+  "packageRules": [
+    {
+      "matchUpdateTypes": [
+        "minor",
+        "patch"
+      ],
+      "groupName": "Minor Updates",
+      "labels": [
+        "minor"
+      ]
+    },
+    {
+      "matchUpdateTypes": [
+        "major"
+      ],
+      "groupName": "Major Updates",
+      "labels": [
+        "major"
+      ]
+    },
+    {
+      "matchManagers": [
+        "github-actions"
+      ],
+      "groupName": "GitHub Actions"
+    }
+  ]
+}