Update ruby/setup-ruby action to v1.278.0 (#1966)

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@8a836efbcebe5de0fe86b48a775b7a31b5c70c93 # v1.277.0
+        uses: ruby/setup-ruby@4c24fa5ec04b2e79eb40571b1cee2a0d2b705771 # v1.278.0
         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@8a836efbcebe5de0fe86b48a775b7a31b5c70c93 # v1.277.0
+        uses: ruby/setup-ruby@4c24fa5ec04b2e79eb40571b1cee2a0d2b705771 # v1.278.0
         with:
           ruby-version: 3.4.8