fix(changelog): resolve issue when @ symbol appears earlier in entry than the contributor

[ReenigneArcher]

Description

In some cases the @ symbol could appear earlier in the line, causing the regex to fail to find the username.

Screenshot

Issues Fixed or Closed

Type of Change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Dependency update (updates to dependencies)
• Documentation update (changes to documentation)
• Repository update (changes to repository files, e.g. .github/...)

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated the in code docstring/documentation-blocks for new or existing methods/components

Branch Updates

LizardByte requires that branches be up-to-date before merging. This means that after any PR is merged, this branch
must be updated before it can be merged. You must also
Allow edits from maintainers.

• I want maintainers to keep my branch updated

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.69%. Comparing base (a5aef49) to head (c8f7f3b).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #112   +/-   ##
=======================================
  Coverage   98.68%   98.69%           
=======================================
  Files           1        1           
  Lines         152      153    +1     
=======================================
+ Hits          150      151    +1     
  Misses          2        2           

Files	Coverage Δ
action/main.py	98.69% <100.00%> (+<0.01%)	⬆️