Update ph_authors.yml

[anisa-hawes]

Update Melvin Hersent affiliation + bio

Note: bio in FR provided by Melvin.

Closes #3694

Checklist

• Assign yourself in the "Assignees" menu
• Add the appropriate "Label"
• If this PR closes an Issue, add the phrase Closes #ISSUENUMBER to your summary above
• Ensure the status checks pass: if you have difficulty fixing build errors, please contact our Publishing Manager @anisa-hawes
• Check the Netlify Preview: navigate to netlify/ph-preview/deploy-preview and click 'details' (at right)
• Assign at least one individual or team to "Reviewers"
  • [ ] if the text needs to be translated, please follow the translation request guidelines, then assign the relevant language team(s) as "Reviewers" and tag both the team as well as the managing editor in your PR.

[jenniferisasi]

Glad to approve this change!