Update version to 0.0.21

Author: sbis04

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.0.21
+
+- Add `--as-debug` option.
+
 ## 0.0.20
 
 - Add `--commit-hash` option.

pubspec.yaml

@@ -1,12 +1,12 @@
 name: flutterflow_cli
 description: >-
   Command-line client for FlutterFlow. Export code from FlutterFlow projects.
-version: 0.0.20
+version: 0.0.21
 homepage: https://github.com/FlutterFlow/flutterflow-cli
 issue_tracker: https://github.com/flutterflow/flutterflow-issues
 
 environment:
-  sdk: '>=2.17.0 <4.0.0'
+  sdk: ">=2.17.0 <4.0.0"
 
 dependencies:
   archive: ^3.3.5