Have any PAKE extensions been added to TLS 1.3?
Has anything been done since then to add PAKE support to TLS 1.3? Are there any active proposals?

No, nothing has been done, and there are no active drafts.
One possible reason for this (I don't know if this is the reason; it sounds plausible to me) is that the TLS working group is waiting for the CFRG [1] to complete its study of PAKEs; the CFRG is mostly done; they have selected OPAQUE as the recommendation if you need an asymmetric PAKE (the server doesn't need to know, which fits how TLS would use it) [2], however just selecting the winner is not sufficient - they need to put together an RFC that explains exactly how to use it (and how to avoid various subtle pitfalls).
Once the CFRG has put together such an RFC, I would expect that a proposal to use it within TLS will be submitted (of course, you are welcome to submit such a proposal)
[1] The Crypto Forum Research Group; that's a group whose purpose is to make recommendations about cryptography to the various IETF working groups
[2] And the winner in the symmetric case would be CPACE; however that is less likely to be used in TLS, as it requires the server to have a copy of the password