added light github theme

lua/custom/plugins/github-nvim-theme.lua

@@ -0,0 +1,13 @@
+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'
+  end,
+}