Update maintainer email

[jennuine]

Summary

Updated the maintainer email in the README.

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[codecov]

Codecov Report

Merging #521 (b76713f) into ign-gui3 (f70933c) will not change coverage.
The diff coverage is n/a.

❗ Current head b76713f differs from pull request most recent head cb77088. Consider uploading reports for the commit cb77088 to get more accurate results

@@            Coverage Diff            @@
##           ign-gui3     #521   +/-   ##
=========================================
  Coverage     73.82%   73.82%           
=========================================
  Files            30       30           
  Lines          3270     3270           
=========================================
  Hits           2414     2414           
  Misses          856      856           

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