Update actions/checkout action to v3

[renovate[bot]]

This PR contains the following updates:

Package	Type	Update	Change
actions/checkout	action	major	v2 -> v3

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Release Notes

actions/checkout

### [`v3`](https://togithub.com/actions/checkout/compare/v2...v3) [Compare Source](https://togithub.com/actions/checkout/compare/v2...v3)

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Configuration

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[codecov[bot]]

Codecov Report

Merging #59 (1a28d27) into master (59a2e21) will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #59   +/-   ##
=======================================
  Coverage   94.44%   94.44%           
=======================================
  Files           6        6           
  Lines         144      144           
  Branches       19       19           
=======================================
  Hits          136      136           
  Misses          8        8           

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