docs: add required key to all versions in the version schema

[zepatrik]

https://github.com/ory/hydra/runs/8022044955?check_suite_focus=true

[codecov]

Codecov Report

Merging #3233 (b1d2c0e) into master (1a6c220) will not change coverage.
The diff coverage is n/a.

❗ Current head b1d2c0e differs from pull request most recent head 8e64bfb. Consider uploading reports for the commit 8e64bfb to get more accurate results

@@           Coverage Diff           @@
##           master    #3233   +/-   ##
=======================================
  Coverage   79.28%   79.28%           
=======================================
  Files         111      111           
  Lines        8107     8107           
=======================================
  Hits         6428     6428           
  Misses       1262     1262           
  Partials      417      417           

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