Clarify deprecation or orUpdate

[Jacse]

It would look like both onConflict and orUpdate were deprecated with no description on what to use or why

Description of change

With this change onConflict was deprecated in favour of orUpdate, but at the same time the "old" call signature of orUpdate was also deprecated. For people that are using the old call signature of orUpdate it now looks like both functions are deprecated with no explanation or alternative offered. This PR introduces a small message to clarify that it is only the one call signature that is deprecated, the function should still be used.

Pull-Request Checklist

• Code is up-to-date with the master branch
• npm run format to apply prettier formatting
• npm run test passes with this change
• This pull request links relevant issues as Fixes #0000 (N/A)
• There are new or updated unit tests validating the change (N/A)
• Documentation has been updated to reflect this change
• The new commits follow conventions explained in CONTRIBUTING.md

[pleerock]

if we go with this change, it's better to document what exactly to use instead.

[Jacse]

Updated so the message now looks like

I juggled with a few different ways to write it and this seemed like the best solution.

[pleerock]

thank you!

[gempain]

@Jacse how do you provide a WHERE condition after the ON CONFLICT DO UPDATE SET ... WHERE which is allowed in Postgres ?