Bump phpmailer/phpmailer from 6.5.0 to 6.5.1

Bumps phpmailer/phpmailer from 6.5.0 to 6.5.1.

• Release notes
• Changelog
• Commits

updated-dependencies:

• dependency-name: phpmailer/phpmailer
  dependency-type: direct:production
  update-type: version-update:semver-patch
  ...

Signed-off-by: dependabot[bot] support@github.com

Co-authored-by: dependabot[bot] 49699333+dependabot[bot]@users.noreply.github.com

Fixes 0029025, PR https://github.com/mantisbt/mantisbt/pull/1777