[Housekeeping] Relax pyarrow constraint

[eapolinario]

Describe the issue

In flyteorg/flytekit#743 we bumped pyarrow minimal version from 3.0.0 to 6.0.0, the idea being that this would allow for a smoother installation on Apple M1 Macs. However, this was too restrictive, as there are clients out there that have pinned versions of pyarrow below 6.0.0. So in order to accommodate these clients, we can have the best of both worlds if we relax that constraint (from requiring at least 6.0.0 to requiring at least 4.0.0).

What if we do not do this?

Some clients will not be able to install flytekit.

Related component(s)

flytekit

Are you sure this issue hasn't been raised already?

• Yes

Have you read the Code of Conduct?

• Yes