Setup ruby to build ci matrix

to use Bundler in rbwasm command

Author: kateinoigakukun

.github/workflows/build.yml

@@ -75,6 +75,10 @@ jobs:
       entries: ${{ steps.set-matrix.outputs.entries }}
     steps:
       - uses: actions/checkout@v4
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: "3.2"
+          bundler-cache: true
       - run: rake ci:pin_build_manifest
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}