Concourse upgrade

[Dyanngg]

Upgrading concourse pipeline to 4.2.1

• Added local user in docker-compose.yaml to satisfy auth requirements for concourse 4.2.1
• Updated fly login command
• Enabled https proxy env variables
• Updated pre-built docker nsx-t-install image

[vmwclabot]

@Dyanngg, you must sign every commit in this pull request acknowledging our Developer Certificate of Origin before your changes are merged. This can be done by adding Signed-off-by: John Doe <john.doe@email.org> to the last line of each Git commit message. The e-mail address used to sign must match the e-mail address of the Git author. Click here to view the Developer Certificate of Origin agreement.

• Commit 110559ec0c072b42cc41d298c5c361cb6512adbf must be signed by yxd155@case.edu
• Commit 658be42f60ba91ad49a1417c3acb25c1749c2224 must be signed by yxd155@case.edu

[kais66]

LGTM. Thanks Yang. Let's get some help with testing the change a bit more before merging it to master.