Spark binary should not be downloaded at build-time

Noticed that spark is downloaded at build-time:
[ 86%] Performing download step (download, verify and extract) for 'fetch-spark-source'
– Downloading...
dst='/home/hadoop/GIT/HPCC-build/downloads/spark-2.4.3-bin-hadoop2.7.tgz'
timeout='300 seconds'
– Using src='https://archive.apache.org/dist/spark/spark-2.4.3/spark-2.4.3-bin-hadoop2.7.tgz'
– [download 0% complete]
– [download 1% complete]
– [download 2% complete]
– [download 3% complete]
– [download 4% complete]
– [download 5% complete]

the spark binary should be submoduled in an attempt to avoid downloading many times.