CONTRIBUTING.md link fix

[m0nclous]

Description

The previous link directed to a 404 page

Type of change

• Bug fix (non-breaking change which fixes an issue)
• Refactor (refactoring a current feature, method, etc...)
• Code Coverage (adding/removing/updating/refactoring tests)
• New feature (non-breaking change which adds functionality)
• Remove feature (non-breaking change which removes functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.95%. Comparing base (46b8001) to head (783c9a7).

Additional details and impacted files

@@            Coverage Diff            @@
##               12.x     #749   +/-   ##
=========================================
  Coverage     89.95%   89.95%           
  Complexity      393      393           
=========================================
  Files           184      184           
  Lines          1185     1185           
=========================================
  Hits           1066     1066           
  Misses          119      119           

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