Update dependency MailKit to 4.13.0

[thomhurst]

This PR contains the following updates:

Package	Type	Update	Change
MailKit (source)	nuget	minor	4.12.1 -> 4.13.0

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.82%. Comparing base (cf3eb3a) to head (7079fed).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1140      +/-   ##
==========================================
+ Coverage   80.77%   80.82%   +0.04%     
==========================================
  Files         215      215              
  Lines        4042     4042              
  Branches      497      497              
==========================================
+ Hits         3265     3267       +2     
+ Misses        651      650       -1     
+ Partials      126      125       -1     

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