Add minimal lazy configuration with example for quick start

[DominikOcsofszki]

Thank you for creating and maintaining this plugin.

As a new user, I found it a bit difficult to get started quickly because the README doesn’t currently include a minimal, working usage example. While the documentation explains the setup and configuration options, a simple example (like a key mapping for incrementing numbers, booleans or dates) would go a long way in helping others onboard faster.

For example, a section like the following could be really helpful:

Installation

Using lazy.nvim

return {
	"monaqa/dial.nvim",
	config = function()
		local augend = require("dial.augend")
		require("dial.config").augends:register_group {
			default = {
				augend.constant.alias.bool,
				augend.integer.alias.decimal_int,
				augend.date.alias["%d.%m.%Y"],
			},

		}
		vim.keymap.set("n", "<C-a>", require("dial.map").inc_normal(), { noremap = true })
		vim.keymap.set("n", "<C-x>", require("dial.map").dec_normal(), { noremap = true })
	end
}

I'd be happy to open a PR with this or help contribute it if that would be useful.

Thanks again for your work on this!