Set maintain_size to True by default

[alifeee]

This behaviour should be default, as discussed in.

#1289

However, this is a breaking change - so should be added at the next major release (6.0.0)

[alifeee]

(since get is one of the most used methods, this "breaking change" should be carefully considered)

[alifeee]

@lavigne958 this is the final issue left in 6.0.0

it requires thought.

For now, I suggest we leave it as False, so it works the same way as before, for maximum backwards compatibility,, and close this issue with no change. What do you think?

[lavigne958]

Agreed let's leave it like this for now.