fix: regex pattern matching

[kounoike]

#50 didn't fix #38. because [[ "abc" == $pattern ]] is simple string match. for regex match, should be [[ "abc" =~ $pattern ]].

this PR fix it.

this PR also fix document. ignore pattern is regex, NOT glob.

[johnlk]

This change takes the wildcard matching and switches us to regex matching. Both are acceptable options. As a point of opinion, wildcard matching feels more ergonomic.

If we did want to support regex matching, maybe this should be another param like regex_files_to_ignore?