Docker image non-functional

[albertor24]

Issue Summary

The instructions in the docker folder are not up to date, and some commands do not work. Moreover, it will be trying to download Prism v3, which will not run when used in the form specified in entrypoint.sh.

Steps to Reproduce

1. Follow the steps in USAGE.md

Expected behaviour:

Instructions are correct

Actual behaviour:

./gradlew test will fail
prism won't run

Technical details:

• sendgrid-java Version: master
• Java Version: As shown in the container

bash-4.2# java -version
java version "1.8.0_211"

I have a PR ready for this, but let me know anything that you may want it to be done differently, or if docker support may be dropped in the future.

[thinkingserious]

Thank you @albertor24! '

We've added this to our backlog for a code review.

With best regards,

Elmer

[childish-sambino]

Fixed by #626