Add api_versions property to Instance entity.

[bocops]

Description

This property will be available starting with Mastodon v4.3.0 as information about the API version offered by a Mastodon server.

See #483.

Type of Change

• New feature

Breaking Changes

None

How Has This Been Tested?

Using existing GetInstanceInfo sample on different Mastodon servers to make sure that for example mastodon.social returns apiVersions.mastodon=2, while other servers not yet running v4.3.0 return apiVersions.mastodon=0

Mandatory Checklist

• I ran gradle check and there were no errors reported
• I have performed a self-review of my code
• I have added tests that prove my fix is effective or that my feature works
• All tests pass locally with my changes
• I have added KDoc documentation to all public methods

Optional checks

• Did you also update the documentation in the /docs folder (e.g. API Coverage page)?

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 49.95%. Comparing base (8b34209) to head (0781147).
Report is 43 commits behind head on master.

Files with missing lines	Patch %	Lines
.../main/kotlin/social/bigbone/api/entity/Instance.kt	50.00%	3 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #484      +/-   ##
============================================
- Coverage     49.99%   49.95%   -0.04%     
+ Complexity      774      773       -1     
============================================
  Files           176      174       -2     
  Lines          5107     4582     -525     
  Branches        327      268      -59     
============================================
- Hits           2553     2289     -264     
+ Misses         2275     2127     -148     
+ Partials        279      166     -113     

Files with missing lines	Coverage Δ
.../main/kotlin/social/bigbone/api/entity/Instance.kt	60.62% <50.00%> (-2.85%)	⬇️

... and 158 files with indirect coverage changes

[andregasser]

Looks good, thx!