This is a feature request to add support for OAUTHBEARER Authentication,
which became recently available in PostgreSQL 18.

Relevant technical links:

• https://www.postgresql.org/docs/18/auth-oauth.html
• https://www.postgresql.org/docs/18/sasl-authentication.html#SASL-OAUTHBEARER
• https://neon.com/postgresql/postgresql-18/oauth-authentication
• https://en.wikipedia.org/wiki/OAuth
• https://oauth.net

At the Frontend/Backend Protocol level, presenting a previously obtained bearer token
should not be too difficult as it resembles the SASL SCRAM-SHA-256 method which is already implemented in P3.

Obtaining a token automatically with a client side flow will be more work.
This requires more configuration and interaction with a browser and an OAuth server.

Testing this feature is non-trivial as it requires a relatively complex setup.
Furthermore, this is a new addition to PostgreSQL.