[Mapbox Java] Add changelog for 7.8.0

[mapbox-github-ci-writer-public-1]

changelog 7.8.0

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.14%. Comparing base (d7b224d) to head (28b8f1d).
⚠️ Report is 4 commits behind head on main.

@@            Coverage Diff            @@
##               main    #1623   +/-   ##
=========================================
  Coverage     78.14%   78.14%           
  Complexity     1070     1070           
=========================================
  Files           161      161           
  Lines          4503     4503           
  Branches        626      626           
=========================================
  Hits           3519     3519           
  Misses          715      715           
  Partials        269      269           

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