Shorten lines of Dockerfile (#860)
Shorten lines of Dockerfile (#860)

* Shorten lines of Dockerfile

* correct Dockerfile syntax

* correct Dockerfile syntax

* correct Dockerfile syntax

sql-machine-learning/sqlflow,sql-machine-learning/sqlflow,sql-machine-learning/sqlflow,sql-machine-learning/sqlflow,sql-machine-learning/sqlflow,sql-machine-learning/sqlflow