Update ruby/setup-ruby action to v1.281.0 (#1970)

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/pr-build.yml

@@ -24,7 +24,7 @@ jobs:
           node-version: 24.12.0
 
       - name: Set up Ruby 3.2
-        uses: ruby/setup-ruby@d5f787ce339eb0767271bc01d922e85644c2c8ab # v1.280.0
+        uses: ruby/setup-ruby@675dd7ba1b06c8786a1480d89c384f5620a42647 # v1.281.0
         with:
           ruby-version: 3.4.8
 

.github/workflows/site-build.yml

@@ -24,7 +24,7 @@ jobs:
           node-version: 24.12.0
 
       - name: Set up Ruby 3.2
-        uses: ruby/setup-ruby@d5f787ce339eb0767271bc01d922e85644c2c8ab # v1.280.0
+        uses: ruby/setup-ruby@675dd7ba1b06c8786a1480d89c384f5620a42647 # v1.281.0
         with:
           ruby-version: 3.4.8