update build system requirements
# Garden Linux Build Scripts
-## build system recommendations
+## build system recommendations (per concurrent build)
- min 2 Cores
- min. RAM 16 GB (image is built in RAM)
- min. 5 GB free disk space
+- 2+ CPU Cores
+- 2+ GiB (use RAM-disk; use fs with sparese-file support)
+- 10+ GiB free disk space
## Documentation
