Support zstd compressed files

[graeme-a-stewart]

This PR makes a small enhancement to support reading Zstd compressed files (*.zst). Zstd can get 20% better compression than Gzip and reading is as fast (unlike LZMA).

File opening is abstracted using a small utility wrapper, so reduces code duplication.

Closes #131

[graeme-a-stewart]

@Moelf - I was a little surprised not to find a generic utility to wrap the correct stream function. Did I miss anything?

OTOH it's so not exactly rocket science, so maybe everyone just does roll their own...

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 73.89%. Comparing base (9771aa4) to head (cc8bc3b).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #132      +/-   ##
==========================================
+ Coverage   73.81%   73.89%   +0.08%     
==========================================
  Files          18       18              
  Lines        1245     1249       +4     
==========================================
+ Hits          919      923       +4     
  Misses        326      326              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[Moelf]

Did I miss anything?

I don't think you missed something, cuz we see https://github.com/JuliaIO/TranscodingStreams.jl/blob/ea4533afaf175443198f5d98009266b6b5f2d882/docs/src/examples.md?plain=1#L101-L110 in their example...