feat(archive): support .tzst suffix

[sorairolake]

See https://lists.gnu.org/archive/html/info-gnu/2019-01/msg00001.html:

When '-a' option is in effect, zstd compression is selected if the
destination archive name ends in '.zst' or '.tzst'.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.75%. Comparing base (c68d830) to head (5f2a1ee).
Report is 275 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4870      +/-   ##
==========================================
- Coverage   83.77%   83.75%   -0.02%     
==========================================
  Files         135      139       +4     
  Lines       13029    11224    -1805     
==========================================
- Hits        10915     9401    -1514     
+ Misses       1677     1359     -318     
- Partials      437      464      +27     

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[caarlos0]

hey! thanks for the PR!

for full transparency: I plan to release v2 as 1.26 minus the deprecations, so this will probably land in v2.1 only.

I'm aiming to release v2 either this weekend or the next, depending if I get any bug reports during this time