Set max-parallel to 3

Signed-off-by: Evan Lezar <elezar@nvidia.com>

Author: elezar

.github/workflows/image.yaml

@@ -31,6 +31,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
+      max-parallel: 3
       matrix:
         sample:
         - devicequery