Final touches before new major release

[fpseverino]

• Remove unused set for stored client
• Update to VaporTesting

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.15%. Comparing base (1a24f07) to head (33d741b).
Report is 1 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main      #51       +/-   ##
===========================================
+ Coverage   80.76%   96.15%   +15.38%     
===========================================
  Files           2        2               
  Lines          26       26               
===========================================
+ Hits           21       25        +4     
+ Misses          5        1        -4     

Files with missing lines	Coverage Δ
Sources/SendGrid/Application+SendGrid.swift	95.83% <100.00%> (+16.66%)	⬆️