Seems pip couldn't tell that pdfminer.six 20250506 >= 20200101. This package
doesn't seem to be imported directly, so removing the dependency, assuming it's
a sub-dependency.
Also removed updated package URL to Forgejo.
Beancount v3 has been recently released. It's a major rewrite and is currently
unstable and not compatible with this codebase. We need to remain on v2.
Unfortunately this is becoming more trouble than it's worth as we
call more and more untyped Beancount functions.
disallow_untyped_defs provides most of the value of what we really
want here, so go ahead and turn this off.
Mostly this meant giving annotations to low-value functions like
the error classes and __init_subclass__, but it's worth it for
the future strictness+documentation value.
