Fix key update

[janste63]

Found a problem in 1.7.0 when updating key bundles with a new set of keys, the old keys were lost.
Fixed typo in a log stmt.
To make this PR complete we should add a new test case to cover this.

[codecov-commenter]

Codecov Report

Merging #117 (feef024) into main (633118d) will decrease coverage by 0.15%.
The diff coverage is 92.30%.

@@            Coverage Diff             @@
##             main     #117      +/-   ##
==========================================
- Coverage   77.42%   77.26%   -0.16%     
==========================================
  Files          41       41              
  Lines        4328     4324       -4     
  Branches      838      836       -2     
==========================================
- Hits         3351     3341      -10     
- Misses        712      718       +6     
  Partials      265      265              

Impacted Files	Coverage Δ
src/cryptojwt/key_bundle.py	78.80% <92.30%> (-0.41%)	⬇️
src/cryptojwt/jwk/hmac.py	75.82% <0.00%> (-4.40%)	⬇️

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