Jib CLI proxy usage not documented

[scrat98]

There is no documentation that we can configure JVM options (You can also use JAVA_OPTS and JIB_OPTS to pass JVM options) for jib cli. That's needed when we want to configure proxy that will be used by jib-core under the hood. But as soon there is a plan to make jib cli native executable it will be better to add proxy options as a cli parameters.

Configure http proxy to use by jib cli:

  JIB_OPTS: >-
    -Dhttp.proxyHost=$PROXY_HOST
    -Dhttp.proxyPort=$PROXY_PORT
    -Dhttps.proxyHost=$PROXY_HOST
    -Dhttps.proxyPort=$PROXY_PORT
    -Dhttp.nonProxyHosts=$NO_PROXY