Migrate structopt from to clap. It had an issue with its dependency, …

…atty, found via https://github.com/paazmaya/filecounter-to-lear-rust/security/dependabot/1

TeXitoi/structopt#525

Cargo.toml

@@ -10,8 +10,8 @@ license = "MIT"
 [dependencies]
 
 # Parse command line argument by defining a struct
-# https://crates.io/crates/structopt
-structopt = "0.3"
+# https://github.com/clap-rs/clap/
+clap = { version = "3.0", features = ["derive"] }
 
 # Recursively walk a directory
 # https://crates.io/crates/walkdir

src/main.rs

@@ -4,18 +4,18 @@ use crate::file_counter::*;
 
 // Add the necessary imports
 use std::path::PathBuf;
-use structopt::StructOpt;
+use clap::StructOpt;
 
 // Define the command-line options using structopt
 #[derive(StructOpt)]
 struct Cli {
     #[structopt(parse(from_os_str))]
     directory: PathBuf,
 
-    #[structopt(short = "e", long = "extensions")]
+    #[structopt(short = 'e', long = "extensions")]
     extensions: Vec<String>,
 
-    #[structopt(short = "r", long = "recursive")]
+    #[structopt(short = 'r', long = "recursive")]
     recursive: bool,
 }