[deps]: Update dtolnay/rust-toolchain digest to 21dc36f

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
dtolnay/rust-toolchain	action	digest	d8352f6 -> 21dc36f

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Configuration

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[bitwarden-bot]

Internal tracking:

• ID: PM-9139
• Link: https://bitwarden.atlassian.net/browse/PM-9139

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 59.25%. Comparing base (4b1d6a1) to head (a539b56).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #855   +/-   ##
=======================================
  Coverage   59.25%   59.25%           
=======================================
  Files         192      192           
  Lines       12585    12585           
=======================================
  Hits         7457     7457           
  Misses       5128     5128           

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