ci.yml in slack-ruby-block-kit-0.12.0

- old
+ new

@@ -13,13 +13,9 @@
     strategy:
       fail-fast: false
       matrix:
         ruby: [ '2.6', '2.7' ]
         experimental: [ false ]
-        include:
-          - ruby: 'head'
-            experimental: true
-
     name: Ruby ${{ matrix.ruby }}
     steps:
       - uses: actions/checkout@v2
       - uses: ruby/setup-ruby@v1
         with: