feat: support windows

Summary:
Add windows support by checking `dll` instead of `so` or `dylib` on windows in `libivy.lua`

Author: @ShaolunWang
Imported From: #90

Test Plan: None provided provided by the author.

Differential Revision: https://ph.baln.co.uk/D7

lua/ivy/libivy.lua

@@ -1,7 +1,22 @@
 local library_path = (function()
   local root = string.sub(debug.getinfo(1).source, 2, #"/libivy.lua" * -1)
   local release_path = root .. "../../target/release"
-  return package.searchpath("libivyrs", release_path .. "/?.so;" .. release_path .. "/?.dylib;")
+  local current_vim_version = vim.version()
+  local minimum_supported_version = vim.version.parse "0.9.5"
+
+  local is_windows
+
+  if vim.version.gt(current_vim_version, minimum_supported_version) then
+    is_windows = vim.uv.os_uname().sysname == "Windows_NT"
+  else
+    is_windows = vim.loop.os_uname().sysname == "Windows_NT"
+  end
+
+  if is_windows then
+    return package.searchpath("ivyrs", release_path .. "/?.dll;")
+  else
+    return package.searchpath("libivyrs", release_path .. "/?.so;" .. release_path .. "/?.dylib;")
+  end
 end)()
 
 local ffi = require "ffi"