create install directory before diff if needed

src/diff.rs

@@ -5,6 +5,7 @@ use terminal_size::{terminal_size, Width};
 use crate::{config::Config, utils::get_tree_files};
 
 pub async fn diff(config: &Config, diff_command: String) -> anyhow::Result<()> {
+	tokio::fs::create_dir_all(&config.install_dir).await?;
 	let built_files = get_tree_files(config, &config.build_dir).await?;
 	let installed_files = get_tree_files(config, &config.install_dir).await?;