ci: prevent injection in presubmit (#55)

Author: averikitsch

.github/workflows/presubmit-tests.yml

@@ -30,7 +30,7 @@ jobs:
       - name: Install toolbox binary
         run: |
           VERSION=$(cat toolbox_version.txt)
-          curl -L -o toolbox https://storage.googleapis.com/genai-toolbox/v$VERSION/linux/amd64/toolbox
+          curl -L -o toolbox "https://storage.googleapis.com/genai-toolbox/v${VERSION}/linux/amd64/toolbox"
           chmod +x toolbox
 
       - name: Install Extension