The regex crate is making the library fairly large. Since we also use fancy_regex, having regex feels redundant. We only need it for its ability to operate over slices rather than just str, but with some refactoring of the vpath function I managed to avoid it entirely, making it possible to remove the dependency.

Along with disabling unicode support for fancy_regex, we get a ~1,7MiB binary (-1MiB). The remaining report shows that fancy_regex is now the main overhead, but unfortunately I don't see a good way to fix it without removing support for pnpIgnorePattern (which is stored as a regex inside the JSON payload):

 File  .text     Size Crate
18.4%  33.9% 313.2KiB std
15.4%  28.4% 262.5KiB regex_automata
 9.8%  18.1% 167.0KiB regex_syntax
 6.0%  11.0% 101.8KiB pnp
 3.4%   6.3%  58.3KiB fancy_regex
 0.8%   1.4%  12.9KiB serde_json
 0.2%   0.4%   3.9KiB serde
 0.2%   0.3%   2.8KiB [Unknown]
 0.2%   0.3%   2.7KiB ryu
 0.1%   0.2%   2.0KiB smallvec
 0.1%   0.2%   2.0KiB hashbrown
 0.1%   0.1%   1.3KiB pathdiff
 0.1%   0.1%   1.3KiB radix_trie
 0.0%   0.1%     792B clean_path
 0.0%   0.0%      20B __rustc
 0.0%   0.0%      12B path_slash
54.3% 100.0% 924.3KiB .text section size, the file size is 1.7MiB

Ref unrs/unrs-resolver#166