ci: use grafana/setup-xk action to install xk6

Author: szkiba

.github/workflows/ci.yml

@@ -23,8 +23,10 @@ jobs:
         with:
           go-version: 1.22.x
           cache: false
-      - name: Install xk6
-        run: go install go.k6.io/xk6/cmd/xk6@latest
+      - name: Setup xk6
+        uses: grafana/[email protected]
+        with:
+          xk6-version: "0.19.2"
       - name: Build
         run: make build
       - name: Test