Problem: nowadays we want all files to store licensing information in
machine-readable format and to use reuse tool to check that. But the
repo is not REUSE compliant.
Solution: add `LICENSES` folder and licensing information for each
file.
Problem: it was agreed with Kostya Ivanov that the copyright owner
is Serokell, so it should be updated in package.yaml.
Also it mentions incorrect license (the one in the repo is MPL-2.0)
and does not have license-file.
Solution: update `copyright` field and `license` field. Also add
`license-file`. Update maintainer as well, because now many people
from Serokell are involved.
I also took the liberty to fix the `github` field.
Problem: latest available LTS resolver is 14.16 and `crossref-verifier`
doesn't compile with it.
Solution: update resolver to 14.16. Newer versions of some packages
are used from now on. I assume that it shouldn't break anything as
long as tests pass.
`req` stopped using `Default` class, that's the only change in the code
I had to make.
Problem: currently `crossref-verify` executable does not work without
configuration, and user was supposed to use one from the repository if
he does not have its own. This is very inconvenient.
Solution: make executable remember some config and use it by default.
For instance, reference to `issues` github page is a valid one despite there is no such
file physically in the repository.
Now user can specify list of "existing" virtual files in config.
