Bump ruby/setup-ruby from 1.278.0 to 1.281.0

Bumps [ruby/setup-ruby](https://github.com/ruby/setup-ruby) from 1.278.0 to 1.281.0.
- [Release notes](https://github.com/ruby/setup-ruby/releases)
- [Changelog](https://github.com/ruby/setup-ruby/blob/master/release.rb)
- [Commits](ruby/setup-ruby@4c24fa5...675dd7b)

---
updated-dependencies:
- dependency-name: ruby/setup-ruby
  dependency-version: 1.281.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/rubyci-alerts.yml

@@ -10,7 +10,7 @@ jobs:
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
 
-      - uses: ruby/setup-ruby@4c24fa5ec04b2e79eb40571b1cee2a0d2b705771 # v1.278.0
+      - uses: ruby/setup-ruby@675dd7ba1b06c8786a1480d89c384f5620a42647 # v1.281.0
         with:
           ruby-version: 2.7
 

.github/workflows/rubyci-screenshot.yml

@@ -14,7 +14,7 @@ jobs:
     steps:
       - uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
 
-      - uses: ruby/setup-ruby@4c24fa5ec04b2e79eb40571b1cee2a0d2b705771 # v1.278.0
+      - uses: ruby/setup-ruby@675dd7ba1b06c8786a1480d89c384f5620a42647 # v1.281.0
         with:
           ruby-version: 2.7