ci: change dependabot target to master branch

Author: tada5hi

.github/dependabot.yml

@@ -3,7 +3,7 @@ updates:
     # Maintain dependencies for GitHub Actions
     - package-ecosystem: "github-actions"
       directory: "/"
-      target-branch: "develop"
+      target-branch: "master"
       schedule:
           interval: "daily"
 
@@ -13,7 +13,7 @@ updates:
       schedule:
           interval: "daily"
       versioning-strategy: "increase"
-      target-branch: "develop"
+      target-branch: "master"
       open-pull-requests-limit: 10
       commit-message:
           prefix: "fix"