Create grouped dependabot.yml (#843)

Co-authored-by: Sindre Sorhus <[email protected]>

.github/dependabot.yml

@@ -0,0 +1,18 @@
+version: 2
+updates:
+ - package-ecosystem: 'github-actions'
+ directory: '/'
+ schedule:
+ interval: 'weekly'
+ groups:
+ github-actions:
+ patterns:
+ - '*'
+ - package-ecosystem: 'npm'
+ directory: '/'
+ schedule:
+ interval: 'weekly'
+ versioning-strategy: 'increase-if-necessary'
+ groups:
+ development-dependencies:
+ dependency-type: 'development'