Use https for all links

Hi all

This is a followup to gtk-rs/gtk#1054

Cheers,
Stefan

Author: dns2utf8

Cargo.toml

@@ -8,7 +8,7 @@ authors = [
 license = "LGPL-2.0"
 description = "LGPL-licensed docs for Gtk-rs crates"
 repository = "https://github.com/gtk-rs/lgpl-docs"
-homepage = "http://gtk-rs.org/"
+homepage = "https://gtk-rs.org/"
 
 [lib]
 name = "lgpl_docs"