src/main.rs: add pre-co command

src/main.rs

 use clap::{Args, Parser, Subcommand};
 
+mod checkout;
 mod commit;
 mod init;
 mod list;
@@ -24,6 +25,9 @@ enum Commands {
     Commit(Commit),
     /// List the content of the .borg archive
     List(List),
+    /// Check if a checkout can be performed without losing data
+    #[clap(name = "pre-co")]
+    PreCo,
 }
 
 #[derive(Debug, Args)]
@@ -54,10 +58,13 @@ fn main() {
             init::init_repository();
         }
         Commands::Commit(commit) => {
-            commit::commit(commit.compression);
+            commit::commit(commit.compression, String::from(""));
         }
         Commands::List(list) => {
             list::borg_list(list.first, list.last, &list.archive);
         }
+        Commands::PreCo => {
+            checkout::prepare_checkout();
+        }
     }
 }