Update plausible submodule

[pppery]

The reason I am doing this for this specific extension is that, through a convoluted but useful series of automated processes, the commit in this repo ends up populating redlinked hooks and categories in the extension infobox.

[hexmode]

Updating the rev the submodule points to isn't strictly necessary. https://codesearch.wmcloud.org/search/ just uses the repo pointer, not the actual revision it points to. But, if you want to update the pointer, I'm not going to argue!