fix(lxd): update LXD version naming support LTS (#532)

[mr-cal]

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Cherry-pick #532 to hotfix/1.20 for snapcraft 7.x

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.01%. Comparing base (76c937b) to head (a7c8ece).

Additional details and impacted files

@@             Coverage Diff              @@
##           hotfix/1.20     #534   +/-   ##
============================================
  Coverage        99.01%   99.01%           
============================================
  Files               57       57           
  Lines             4558     4561    +3     
============================================
+ Hits              4513     4516    +3     
  Misses              45       45           

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[mr-cal]

Test failure is for almalinux 9 not being available. This is OK because the hotfix for this old release is intended for snapcraft 7.x, which doesn't use almalinux.