chore: update ci test step in action (#590)

Author: matthv

.github/workflows/build.yml

@@ -42,7 +42,7 @@ jobs:
     if: "!contains(github.event.head_commit.message, '[skip ci]')"
     steps:
       - uses: actions/checkout@v2
-      - uses: actions/setup-ruby@v1
+      - uses: ruby/setup-ruby@v1
         with:
           ruby-version: 2.7
       - name: Cache gem