fix(template): Use env variable USERNAME in Windows

Author: Nekketsu

Diff for: lua/orgmode/capture/template/init.lua

@@ -6,6 +6,8 @@ local Calendar = require('orgmode.objects.calendar')
 local Promise = require('orgmode.utils.promise')
 local Input = require('orgmode.ui.input')
 
+local is_windows = vim.loop.os_uname().sysname == 'Windows_NT'
+
 local expansions = {
   ['%%f'] = function()
     return vim.fn.expand('%')
@@ -14,7 +16,7 @@ local expansions = {
     return vim.fn.expand('%:p')
   end,
   ['%%n'] = function()
-    return os.getenv('USER')
+    return is_windows and os.getenv('USERNAME') or os.getenv('USER')
   end,
   ['%%x'] = function()
     return vim.fn.getreg('+')