Update ruby/setup-ruby action to v1.88.0

.github/workflows/build.yml

@@ -13,7 +13,7 @@ jobs:
     steps:
     - uses: actions/checkout@v2.4.0
     - name: Set up Ruby
-      uses: ruby/setup-ruby@v1.87.0
+      uses: ruby/setup-ruby@v1.88.0
       with:
         bundler-cache: true # runs 'bundle install' and caches installed gems automatically
     - name: Run tests

.github/workflows/schedule-doc-report.yml

@@ -10,7 +10,7 @@ jobs:
     steps:
     - uses: actions/checkout@v2.4.0
     - name: Set up Ruby
-      uses: ruby/setup-ruby@v1.87.0
+      uses: ruby/setup-ruby@v1.88.0
       with:
         bundler-cache: true # runs 'bundle install' and caches installed gems automatically
     - name: Generate report

.github/workflows/test.yml

@@ -11,7 +11,7 @@ jobs:
     steps:
     - uses: actions/checkout@v2.4.0
     - name: Set up Ruby
-      uses: ruby/setup-ruby@v1.87.0
+      uses: ruby/setup-ruby@v1.88.0
       with:
         bundler-cache: true # runs 'bundle install' and caches installed gems automatically
     - name: Run tests