Bump helm to v2.16.0

[EricLemieux]

What this PR does / why we need it:
Bumps the helm version to v2.16.0

Special notes for your reviewer:
I saw that the v3.0.0 pr is in progress, not sure if you were planning on continuing to support 2.x.x after that is merged.

[scottrigby]

Please change the PR branch to dev-v2 per https://help.github.com/en/github/collaborating-with-issues-and-pull-requests/changing-the-base-branch-of-a-pull-request

The dev-v2 branch is for ongoing chart-testing v2 maintenance. That will include bug fixes. master is now for v3 work, and actively developed, including new features etc.

See #182 for more info about the branch/version change.

[scottrigby]

Also note there is a helm 2.16.1 release planned https://github.com/helm/helm/milestone/78 (see discussion section in this week's helm dev meeting notes). I don't know if that impacts this PR but mentioning just in case.

[scottrigby]

@EricLemieux I went ahead and changed the base branch for you, but now the changes from #183 are in this PR too since you initially created this PR branch from master. Let me know if you need help resolving that.

[EricLemieux]

Changing the target branch changes the scope of this pr, because it now includes #183

Should I adjust as to only include the change I made?

[scottrigby]

Chatting on Slack. That sounds good, will wait for update 👍

[scottrigby]

Given the fixes going into Helm v2.16.1 should we wait for that helm release before releasing another v2 version of chart-testing?

[EricLemieux]

Given the concerns with v2.16.0 I'll close this pr, and come back with a new one when v2.16.1 is released.