- LegacyKeyValueFormat: "ENV key=value" should be used
instead of legacy "ENV key value" format (line 42)
"""
The new format for declaring environment variables in Dockerfiles is ENV
key=value. This format, where the key and value are separated by an
equals sign (=), is the recommended approach. The older format, ENV key
value (with a space as a separator), is deprecated.
""" -- google search