refactor: update for compatibility with asdf v0.16 (#71)

Technically, `asdf plugin list` is supported in old asdf versions as well, but we added a compatibility matrix for completeness.

Author: Eric Griffith

README.md

@@ -27,6 +27,7 @@ ASDF Plugin Manager allows you to pin `asdf` plugin info like Git URL and ref fo
 - [Overview](#overview)
 - [Why?](#why)
 - [Dependencies](#dependencies)
+- [Compatibility](#compatibility)
 - [Install](#install)
 - [Example](#example)
 - [Parameters](#parameters)
@@ -49,6 +50,15 @@ Hence, `asdf-plugin-manager` fills the gap to manage asdf plugins securely and d
 - `ASDF_PLUGIN_MANAGER_PLUGIN_VERSIONS_FILENAME`: Set the default name for the file with the list of managed plugins.
   Default: `.plugin-versions`.
 
+# Compatibility
+
+Since the release of ASDF `v0.16.0` there have been a number of [breaking changes](https://asdf-vm.com/guide/upgrading-to-v0-16.html) as it was [completely rewritten](https://github.com/asdf-vm/asdf/releases/tag/v0.16.0). Use the table below to determine which version of `asdf-plugin-manager` to use.
+
+| ASDF Version           | Compatible Plugin Manager Version |
+|------------------------|-----------------------------------|
+| v0.15.0 (or older)     | v1.4.0 (or older)                 |
+| v0.16.0 (or newer)     | v1.5.0 (or newer)                 |
+
 # Install
 
 > **Note**

cli/asdf-plugin-manager.sh

@@ -71,7 +71,7 @@ print_git_compare_url() {
 }
 
 export_plugins() {
-    asdf plugin-list --refs --urls | tr -s ' ' | cut -d ' ' -f 1,2,4 | column -t
+    asdf plugin list --refs --urls | tr -s ' ' | cut -d ' ' -f 1,2,4 | column -t
 }
 
 # Mimic 'asdf plugin update' to avoid "fatal: couldn't find remote ref ...".