Bump ruby/setup-ruby from 1.235.0 to 1.266.0

Bumps [ruby/setup-ruby](https://github.com/ruby/setup-ruby) from 1.235.0 to 1.266.0.
- [Release notes](https://github.com/ruby/setup-ruby/releases)
- [Changelog](https://github.com/ruby/setup-ruby/blob/master/release.rb)
- [Commits](ruby/setup-ruby@dffc446...4ff6f36)

---
updated-dependencies:
- dependency-name: ruby/setup-ruby
  dependency-version: 1.266.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -18,7 +18,7 @@ jobs:
         ]
     steps:
     - uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5 # v2.7.0
-    - uses: ruby/setup-ruby@dffc446db9ba5a0c4446edb5bca1c5c473a806c5 # v1.235.0
+    - uses: ruby/setup-ruby@4ff6f3611a42bc75eee1e5138240eb1613f48c8f # v1.266.0
       with:
         ruby-version: ${{ matrix.ruby }}
         bundler-cache: true
@@ -28,7 +28,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5 # v2.7.0
-      - uses: ruby/setup-ruby@dffc446db9ba5a0c4446edb5bca1c5c473a806c5 # v1.235.0
+      - uses: ruby/setup-ruby@4ff6f3611a42bc75eee1e5138240eb1613f48c8f # v1.266.0
         with:
           bundler-cache: true
       - run: sudo apt-get install -y valgrind