fix: do not download cached files

[stephenplusplus]

Fixes #566

To quickly sum up the issue discovered in #566, this works:

• Save file with contents 'a'
• Download file. Contents === 'a'
• Save file with contents 'b'
• Download file. Contents === 'b' 😄

But as soon as it's a public file, it doesn't work:

• Save file with contents 'a'
• Make file public
• Download file. Contents === 'a'
• Save file with contents 'b'
• Download file. Contents === 'a' 😢

I believe what happens when the file is flipped to a public object, we then have to worry about caching. When you update the file, the upstream API's generation property is updated as well for the Object record.

So far, I've found three solutions:

• Ensure the file we download will not be cached (Cache-Control: no-store)
• Set Cache-Control: no-transform on the file's metadata
• Send the download API request with the latest generation in the query

I went with the first, as it seems the least error-prone.

[codecov]

Codecov Report

Merging #643 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #643   +/-   ##
=======================================
  Coverage   97.94%   97.94%           
=======================================
  Files           9        9           
  Lines         874      874           
  Branches       99       99           
=======================================
  Hits          856      856           
  Misses          9        9           
  Partials        9        9

Impacted Files	Coverage Δ
src/file.ts	98.64% <ø> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 519ba1b...82127cc. Read the comment docs.