Add release 1.16 to metadata.yaml

[mboersma]

/kind cleanup

What this PR does / why we need it:

Adds the impending 1.16 release series to metadata.yaml so its API version is found, and all that good stuff.

Which issue(s) this PR fixes:

N/A, but see #4821 for prior art.

Special notes for your reviewer:

• cherry-pick candidate

TODOs:

• squashed commits
• includes documentation
• adds unit tests

Release note:

NONE

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 51.18%. Comparing base (1e9f0d9) to head (edb9531).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4986   +/-   ##
=======================================
  Coverage   51.17%   51.18%           
=======================================
  Files         274      274           
  Lines       24625    24625           
=======================================
+ Hits        12603    12605    +2     
+ Misses      11236    11234    -2     
  Partials      786      786           

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[Jont828]

/lgtm
/approve

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 7be0a34535ff9482262e7863d479275353a42cce

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Jont828

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