Require Julia v1.10 (LTS)

[dlfivefifty]

The motivation for this change would be to allow adding extensions without adding unnecessary dependencies for users on pre-v1.10.

In particular, this makes it easier to finish #311

See also JuliaMath/AbstractFFTs.jl#140

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 72.91%. Comparing base (cefd827) to head (8a2fb50).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #312      +/-   ##
==========================================
+ Coverage   70.99%   72.91%   +1.91%     
==========================================
  Files           5        5              
  Lines         531      528       -3     
==========================================
+ Hits          377      385       +8     
+ Misses        154      143      -11     

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[giordano]

I'm not sure this is strictly necessary for adding an extension: the extension would work only in Julia v1.9+, but can exist, without working also in previous releases. Requiring Julia v1.10 nowadays is a good idea regardless though.