Store UNICODE_VERSION as a tuple

Remove the UnicodeVersion struct containing
major, minor and update fields and replace it with
a 3-tuple containing the version number.
As the value of each field is limited to 255
use u8 to store them.

src/tools/unicode-table-generator/src/main.rs

@@ -295,7 +295,7 @@ fn main() {
 
 fn version() -> String {
     let mut out = String::new();
-    out.push_str("pub const UNICODE_VERSION: (u32, u32, u32) = ");
+    out.push_str("pub const UNICODE_VERSION: (u8, u8, u8) = ");
 
     let readme =
         std::fs::read_to_string(std::path::Path::new(UNICODE_DIRECTORY).join("ReadMe.txt"))