Relax SQLAlchemy version dependency

[vsolovyov]

Right now in setup.py we have SQLAlchemy pinned to <1.4.0:

    # SQLAlchemy 1.4.0 breaks flask-sqlalchemy and sqlalchemy-utils
    "SQLAlchemy<1.4.0",

flask-sqlalchemy added support for 1.4 in release 2.5.0 (released in March).
sqlalchemy-utils added support for 1.4 in release 0.37.0 (released in April).

I think we should update SQLAlchemy dependency.

[dpgaspar]

We can't there's still an issue on flask-sqlalchemy: pallets-eco/flask-sqlalchemy#1001
or wait for the next major release (3.0.0) where that issue is solved also

[kyoshi-warrior]

Any update on easing this dependency?
# SQLAlchemy 1.4.0 breaks flask-sqlalchemy and sqlalchemy-utils "SQLAlchemy<1.4.0",
this is breaking as some of our other libraries require SQLAlchemy >= 1.4.0

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed in 7 days if no further activity occurs. Feel free to reopen it if it's still relevant to you. Thank you