aconfig: rename namespace -> package

What used to be referred to as a namespace is now called a package.

This CL is a semantic change only.

Bug: 285000854
Test: m nothing
Test: atest aconfig.test
Change-Id: If3fca67c415af75b44f316e16666b97089407069
diff --git a/tools/aconfig/src/main.rs b/tools/aconfig/src/main.rs
index dab0191..5a820d9 100644
--- a/tools/aconfig/src/main.rs
+++ b/tools/aconfig/src/main.rs
@@ -44,7 +44,7 @@
         .subcommand_required(true)
         .subcommand(
             Command::new("create-cache")
-                .arg(Arg::new("namespace").long("namespace").required(true))
+                .arg(Arg::new("package").long("package").required(true))
                 .arg(Arg::new("declarations").long("declarations").action(ArgAction::Append))
                 .arg(Arg::new("values").long("values").action(ArgAction::Append))
                 .arg(Arg::new("cache").long("cache").required(true)),
@@ -134,10 +134,10 @@
     let matches = cli().get_matches();
     match matches.subcommand() {
         Some(("create-cache", sub_matches)) => {
-            let namespace = get_required_arg::<String>(sub_matches, "namespace")?;
+            let package = get_required_arg::<String>(sub_matches, "package")?;
             let declarations = open_zero_or_more_files(sub_matches, "declarations")?;
             let values = open_zero_or_more_files(sub_matches, "values")?;
-            let cache = commands::create_cache(namespace, declarations, values)?;
+            let cache = commands::create_cache(package, declarations, values)?;
             let path = get_required_arg::<String>(sub_matches, "cache")?;
             let file = fs::File::create(path)?;
             cache.write_to_writer(file)?;