Linux CI

[cbaker6]

• enable most of the tests for linux along with codecov
• Update Swift Linux toolchain to 5.3.3 in CI

[codecov]

Codecov Report

Merging #76 (76042e3) into main (304af69) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main      #76   +/-   ##
=======================================
  Coverage   78.99%   78.99%           
=======================================
  Files          61       61           
  Lines        4903     4903           
=======================================
  Hits         3873     3873           
  Misses       1030     1030           

Impacted Files	Coverage Δ
Sources/ParseSwift/Objects/ParseInstallation.swift	82.07% <ø> (ø)
Sources/ParseSwift/Objects/ParseUser.swift	75.97% <0.00%> (-0.18%)	⬇️
Sources/ParseSwift/Storage/ParseFileManager.swift	90.15% <0.00%> (+0.75%)	⬆️

---

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 304af69...4ce8da4. Read the comment docs.