Fix a couple of Swift 6 warnings

[0xTim]

Fix a couple of warnings in Swift 6

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 78.64%. Comparing base (faa6f73) to head (e3f16f7). Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #182   +/-   ##
=======================================
  Coverage   78.64%   78.64%           
=======================================
  Files          60       60           
  Lines        1405     1405           
=======================================
  Hits         1105     1105           
  Misses        300      300           

Files	Coverage Δ
Sources/JWTKit/EdDSA/EdDSA.swift	94.59% <ø> (ø)