fix(is_template check): swap out call to viml string match function for builtin lua function.

[lamb003]

Hi @epwalsh,

Thanks for the great plugin, I have just noticed this bug on my system. I'm not sure anyone else has experienced it but I thought I'd propose a fix since it seemed pretty straightforward. (Although I'm no Lua expert)

The issue is that for a path to a vault that contained tildes (like a path to a folder in iCloud), the is_template function throws errors when calling the vim matchstr function. Swapping it out for the lua string match function eliminated the error for me.

example setup that previously caused errors.

require("obsidian").setup({
dir="/Users/person/Library/Mobile Documents/iCloud~md~obsidian/Documents/Notes",
    notes_subdir = "fleeting",
    templates = {
      subdir = "Templates",
      date_format = "%Y-%m-%d-%a",
      time_format = "%H:%M"
  },
...

[epwalsh]

Thanks for the quick fix @lamb003!