Update dependencies

[Flix6x]

This includes a new major release of flask-security-too(closes #24). At first glance I think we're good, but maybe you can take a better look at their release notes, too?

[nhoening]

I'd make the dependency on >= 4.0 explicit, as it's non-backward compatible. I added a link to issue #24 where they provide a list of concerning topics, e.g. emailing.

There is no need to do this in version 0.2.4 right?

I'd say an issue like this is perfect to handle right after a release.

[Flix6x]

Good suggestion to merge this immediately after release. And I added the minimum requirement just now.

[nhoening]

I think you meant to use >= 4.0 and not <= 4.0?

[Flix6x]

Good catch.

[nhoening]

With the fix to RowProxy (nice work, I noticed this problem before), I believe we are depending on a new version of sqlalchemy >= 1.4, or am I incorrect? If so, I believe that, too, would need to be explicit (we are not backwards-compatible).