Add NeoVim configuration with default font and update setup script

nvim/lua/plugins/theme.lua

@@ -0,0 +1,10 @@
+return {
+    'projekt0n/github-nvim-theme',
+    name = 'github-theme',
+    lazy = false, -- make sure we load this during startup if it is your main colorscheme
+    priority = 1000, -- make sure to load this before all the other start plugins
+    config = function()
+      require('github-theme').setup({})
+      vim.cmd('colorscheme github_dark_default')
+    end,
+  }