Hardcode homepage URL for --version

Setting the homepage in Cargo.toml causes it to annoyingly be duplicated
on crates.io (because it's already got the repository URL.) But
unfortunately there's no CARGO_PKG_REPOSITORY env.

src/main.rs

@@ -95,7 +95,7 @@ fn main() {
                  env!("CARGO_PKG_VERSION"),
                  /* See build.rs for the git-revision.txt file */
                  include!(concat!(env!("OUT_DIR"), "/git-revision.txt")));
-        println!("{}", env!("CARGO_PKG_HOMEPAGE"));
+        println!("https://github.com/C4K3/nbted");
         return;
     }