install ruby in ci

.github/workflows/book.yml

@@ -17,6 +17,9 @@ jobs:
       - uses: actions/checkout@v4
         with:
           fetch-depth: 0
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: '3.4'
       - name: Install latest mdbook
         run: |
           tag=$(curl 'https://api.github.com/repos/rust-lang/mdbook/releases/latest' | jq -r '.tag_name')

.github/workflows/rust.yml

@@ -16,6 +16,9 @@ jobs:
       RUSTFLAGS: -D warnings
     steps:
     - uses: actions/checkout@v3
+    - uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: '3.4'
     - name: Clippy
       run: cargo clippy --all-features --verbose -- -D warnings
     - name: Build