Add support for any utf8 filename or even other encoding supported by spec and filesystems

[HugoPoi]

• filename billstraße-123-hamburg.yml isn't supported and will throw unexpected character 'ß' at position 9
• and Support parsing of CODEOWNERS entries containing the ^ character #47
• and CODEOWNERS patterns crashes on paths containing square brackets [param] #42
• Allow tilde in patterns #50
• Allow any escaped character in pattern #48

Could we implement the CODEOWNERS spec with something similar Yacc / Bison for Go ?
https://www.dolthub.com/blog/2023-07-28-goyacc-parser-tips-tricks/
https://pkg.go.dev/golang.org/x/tools/cmd/goyacc?utm_source=godoc