Alter nullable constraint when alterNullable is set to true

[yhaskell]

As discussed in the #4401 Issue, I created a PR to make it so nullable alterations only apply when ({ alterNullable: true }) is provided as a param to .alter() function (which is a default value, since we do not want to break the previous behaviour).

@elhigu please help further :)

[kibertoad]

Can you also add an integration test? there are few dealing with nullability in integration2, you can build from there

[cpaczek]

This is also an issue on CockroachDB. See: strapi/strapi#11738

[kibertoad]

@OlivierCavadenti this might also look good in 1.0.0

[intech]

@OlivierCavadenti before doing anything, check out this post strapi/strapi#11738 (comment)

[ethan-gallant]

Can we get this merged? It's causing quite a headache for various projects depending on knex.

[kibertoad]

@ethan-gallant tests are missing and there are conflicts. wiuld you like to help?

[OlivierCavadenti]

@OlivierCavadenti before doing anything, check out this post strapi/strapi#11738 (comment)

I can check tomorrow I think. I need to reread the thread to understand the problem ^^.

[kibertoad]

@OlivierCavadenti Do you think we can publish next semver minor now?

[intech]

@OlivierCavadenti as it turned out, this is irrelevant, there is a problem with the requests themselves, just a similar error