feat: floating window max width/height can be percentages (#553)

README.md

@@ -256,6 +256,7 @@ require("oil").setup({
   float = {
     -- Padding around the floating window
     padding = 2,
+    -- max_width and max_height can be integers or a float between 0 and 1 (e.g. 0.4 for 40%)
     max_width = 0,
     max_height = 0,
     border = "rounded",