chore: bump manifest version to v2.21.0

fxmanifest.lua

@@ -8,7 +8,7 @@ rdr3_warning 'I acknowledge that this is a prerelease build of RedM, and I am aw
 --[[ Resource Information ]]--
 name         'ox_lib'
 author       'Linden'
-version      '2.20.0'
+version      '2.21.0'
 license      'LGPL-3.0-or-later'
 repository   'https://github.com/overextended/ox_lib'
 description  'A library of shared functions to utilise in other resources.'