Use ruby/setup-ruby gh action

actions/setup-ruby is deprecated

.github/workflows/build.yml

@@ -15,7 +15,7 @@ jobs:
       - name: Code Checkout
         uses: actions/checkout@v1
       - name: Set Ruby
-        uses: actions/setup-ruby@v1
+        uses: ruby/setup-ruby@v1
         with:
           ruby-version: '2.6'
       - name: Build RubyGem

.github/workflows/code.yml

@@ -15,7 +15,7 @@ jobs:
           persist-credentials: false
           fetch-depth: 0
       - name: Set Ruby
-        uses: actions/setup-ruby@v1
+        uses: ruby/setup-ruby@v1
         with:
           ruby-version: '2.6'
       - name: Sync Blackbox Testing Repository

.github/workflows/release.yml

@@ -15,7 +15,7 @@ jobs:
       - name: Code Checkout
         uses: actions/checkout@v1
       - name: Set Ruby
-        uses: actions/setup-ruby@v1
+        uses: ruby/setup-ruby@v1
         with:
           ruby-version: '2.6'
       - name: Create Builders Release

.github/workflows/testing.yml

@@ -36,7 +36,7 @@ jobs:
       - name: Code Checkout
         uses: actions/checkout@v1
       - name: Setup Ruby
-        uses: actions/setup-ruby@v1
+        uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{matrix.ruby}}
           architecture: 'x64'