Generate shell completions with clap during build (#327)

* Generate shell completions with clap during build

* Updated ci release script, added SHELL_COMPLETIONS_DIR override to build.rs and fixed dependency version

src/main.rs

@@ -19,6 +19,7 @@ extern crate syntect;
 
 mod app;
 mod assets;
+mod clap_app;
 mod controller;
 mod decorations;
 mod diff;