Configure update groups

Try to reduce conflicts when merging dependency updates by grouping updates for
related packages.

See https://docs.github.com/en/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file#groups

.github/dependabot.yml

 version: 2
 updates:
-- package-ecosystem: npm
-  directory: "/"
+  - package-ecosystem: npm
+    directory: '/'
     schedule:
       interval: weekly
-    time: "10:00"
+      time: '10:00'
     open-pull-requests-limit: 10
+    groups:
+      babel:
+        patterns:
+          - '@babel/*'
+      lint:
+        patterns:
+          - 'eslint*'
+          - '@typescript-eslint/'
+      rollup:
+        patterns:
+          - '@rollup/*'
+      sentry:
+        patterns:
+          - '@sentry/*'