Markdown italic/emphasis and bold/strong not working

Thanks for the great theme!

I word with markdown files. When I surround text with I expect the text to show in italic*. When I surround text with I expect the text to show in bold**.

What actually happens is that the text remains unchanged in appearance. The asterisks turn blue.

I tried another theme to see if it was something specific to my setup. Italic and bold both work in the: edge theme

I'm using

github-nvim-theme v0.0.7
NVIM 0.8.3
iTerm2 3.4.19
macOS Ventura 13.2

Text used to test

*italic*
**bold**

My minimal init.lua:

require('packer').startup(function()
  use { 'wbthomason/packer.nvim' }
  use { 'nvim-treesitter/nvim-treesitter',
        run = ':TSUpdate' }
    use { 'projekt0n/github-nvim-theme', branch = '0.0.x' }
end)

require'nvim-treesitter.configs'.setup {
    ensure_installed = { "markdown", "markdown_inline", "lua", "vim", "help" },
    sync_install = false,
    auto_install = true,
    highlight = {
        enable = true,
        disable = { "" },
    additional_vim_regex_highlighting = false,
    },
}

require('github-theme').setup({
    theme_style='light'
})

-- Force use of macOS GUI clipboard
vim.opt.clipboard = 'unnamed'

nvim-treesitter checkhealth:

nvim-treesitter: require("nvim-treesitter.health").check()
========================================================================
## Installation
  - OK: `tree-sitter` found 0.20.7 (parser generator, only needed for :TSInstallFromGrammar)
  - OK: `node` found v14.19.1 (only needed for :TSInstallFromGrammar)
  - OK: `git` executable found.
  - OK: `cc` executable found. Selected from { vim.NIL, "cc", "gcc", "clang", "cl", "zig" }
    Version: Apple clang version 14.0.0 (clang-1400.0.29.202)
  - OK: Neovim was compiled with tree-sitter runtime ABI version 14 (required >=13). Parsers must be compatible with runtime ABI.

## OS Info:
{
  machine = "x86_64",
  release = "22.3.0",
  sysname = "Darwin",
  version = "Darwin Kernel Version 22.3.0: Thu Jan  5 20:53:49 PST 2023; root:xnu-8792.81.2~2/RELEASE_X86_64"
}

## Parser/Features         H L F I J
  - c                   ✓ ✓ ✓ ✓ ✓
  - markdown            ✓ . ✓ . ✓
  - markdown_inline     ✓ . . . ✓
  - help                ✓ . . . ✓
  - vim                 ✓ ✓ ✓ . ✓
  - latex               ✓ . ✓ . ✓
  - lua                 ✓ ✓ ✓ ✓ ✓

  Legend: H[ighlight], L[ocals], F[olds], I[ndents], In[j]ections
         +) multiple parsers found, only one will be used
         x) errors found in the query, try to run :TSUpdate {lang}

NVIM version:

NVIM v0.8.3
Build type: Release
LuaJIT 2.1.0-beta3
Compiled by brew@Ventura

Features: +acl +iconv +tui
See ":help feature-compile"

   system vimrc file: "$VIM/sysinit.vim"
  fall-back for $VIM: "/usr/local/Cellar/neovim/0.8.3/share/nvim"

Run :checkhealth for more info

projekt0n / github-nvim-theme

Markdown italic/emphasis and bold/strong not working #231