Add cdk to dependabot configuration

[Zharktas]

CDK dependencies weren't automatically updating

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 83.07%. Comparing base (91b36f8) to head (e7f28d9).
Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #328   +/-   ##
=======================================
  Coverage   83.07%   83.07%           
=======================================
  Files          20       20           
  Lines        1903     1903           
  Branches        1        1           
=======================================
  Hits         1581     1581           
  Misses        322      322           

Flag	Coverage Δ
cdk	100.00% <ø> (ø)

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