ci: switch to bazel-contrib/setup-bazel action (curl install path unwritable)

Author: avrabe

.github/workflows/validate.yml

@@ -46,13 +46,10 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Install bazelisk
-        run: |
-          curl -fsSL https://github.com/bazelbuild/bazelisk/releases/download/v1.20.0/bazelisk-linux-amd64 \
-              -o /usr/local/bin/bazelisk
-          chmod +x /usr/local/bin/bazelisk
-          ln -s /usr/local/bin/bazelisk /usr/local/bin/bazel
-          bazel --version
+      - name: Set up bazelisk
+        uses: bazel-contrib/setup-bazel@0.9.1
+        with:
+          bazelisk-version: "1.x"
 
       - name: bazel build //... (WIT → wit-bindgen → rust_component → .wasm)
         run: bazel build //...