Add shared credential for Wellfound

[timdream]

Wellfound changed their name from AngelList Talent. They updated their domain from angel.co to wellfound.com accordingly. The same e-mail+password now works on the new domain.

Proof:

• angel.co now directs to wellfound.com.
• Wellfound website header comes with "formerly AngelList Talent" under their logo.

Overall Checklist

• [x] I agree to the project's Developer Certificate of Origin
• [x] The top-level JSON objects are sorted alphabetically
• [x] There are no open pull requests for the same update

for shared-credentials.json

• [x] There's evidence the domains are currently related (SSL certificates, DNS entries, valid links between sites, legal documents etc.)
• [x] If using shared, the new group serves login pages on each of the included domains, and those login pages accept accounts from the others. (For example, we wouldn't use a shared association from google.co.il to google.com, because google.co.il redirects to accounts.google.com for sign in.)
• [x] If using from and to, the new group, the from domain(s) redirect to the to domain to log in.

[timdream]

lol I didn't realize there is already #706.