Fix jq command to extract build number correctly

Author: andygruening

.github/workflows/unity-cloud-check.yml

@@ -26,7 +26,7 @@ jobs:
           build_number=$(curl -s -X POST \
             -H "Authorization: Basic ${{ secrets.UNITY_API_KEY }}" \
             https://build-api.cloud.unity3d.com/api/v1/orgs/6872789246035/projects/5fac262b-e52e-42f7-a9d6-d4464b2ff80e/buildtargets/${{ matrix.target }}/builds \
-            | jq '.build' )
+            | jq '.[0].build' )
 
           echo "build_number=$build_number" >> $GITHUB_OUTPUT