src/create_hooks.rs: add executable permissions to hooks files

src/create_hooks.rs

 use std::fs::File;
 use std::io::Write;
+use std::os::unix::prelude::PermissionsExt;
 use std::{
     path::PathBuf,
     process::{exit, Command},
@@ -73,6 +74,8 @@ fn create_file(folder: &PathBuf, file_name: &str, content: &str) {
         );
         exit(7);
     });
+    let mut permissions = file.metadata().unwrap().permissions();
+    permissions.set_mode(0o755);
 }
 
 /// Create 3 files in `.git/hooks` folder