Add support for specifying allowed auth methods

[vonzshik]

Closes #6035

[Brar]

I actually liked it better before you added the explicit RequireAuthMode.All, because we share PGREQUIREAUTH with libpq and before adding it we were 100% syntax compatible whereas now we have the All mode in addition.

It's not a big deal because our default for the unset option is the same as libpq's (All) but if users explicitly set PGREQIREAUTH to All because they think that it's a good idea or required, they break libpq connections.

[vonzshik]

I actually liked it better before you added the explicit RequireAuthMode.All, because we share PGREQUIREAUTH with libpq and before adding it we were 100% syntax compatible whereas now we have the All mode in addition.

It's not a big deal because our default for the unset option is the same as libpq's (All) but if users explicitly set PGREQIREAUTH to All because they think that it's a good idea or required, they break libpq connections.

I think we can just disallow parsing ALL, it's an internal enum after all, so as long as we do not document it publicly...

[vonzshik]

OK, seems no one has an any other objections. Merging.

[meteortent]

want to know when this commit could be release? will it be in version 9.0.4?

[vonzshik]

want to know when this commit could be release? will it be in version 9.0.4?

We usually do not backport features (and this is a feature) to previous releases, so most likely 10.0 in November.