Slightly more complex than that, as the ECHR isn't an EU institution, so Brexit won't result in any significant change to the relationship with the ECHR (it's a little more complex than I've made sound, as there are some relatively minor links with the EU).

However, May has stated her desire to also leave the European convention on human rights (and replace it with a UK owned Bill of Rights). This is not something that's happening as part of Brexit, and no bills have been presented before Parliament with this as a component or purpose.

I would assume that the government would take the pragmatic approach that it's better to focus on Brexit for now, and deal with the ECHR once Brexit is over with. However, I have no inside knowledge of this, and that's just my wild and unsubstantiated assumption.