Add test dependency to fix linking error in unit tests

[JonPulfer]

I was getting a linking error when trying to run the unit tests. Adding this dependency to HummingbirdRouter fixed that error.

[adam-fowler]

Don't know why CI never caught this. Can you run Nick Lockwood's swiftformat on this change.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.01%. Comparing base (e78cde7) to head (368320f).
Report is 94 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #504      +/-   ##
==========================================
- Coverage   84.86%   83.01%   -1.86%     
==========================================
  Files          98       94       -4     
  Lines        5320     4280    -1040     
==========================================
- Hits         4515     3553     -962     
+ Misses        805      727      -78     

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[JonPulfer]

For some reason, swiftformat in Xcode creates a suspiciously large changes to the formatting of the white space in the file. Running swiftformat on the CLI just updates the whitespace on the line I changed. I have swiftformat v0.53.8 installed.

[adam-fowler]

thank you for this