Bump version

CHANGELOG.md

+# 3,1,9
+- Add `listAllObjects` and `listAllObjectsV2`
+- Fix signing error in `listObjects` when prefix contains spaces [#34]
+- Improved compatibility with Filebase [#31]
+
 # 3.0.0
 - Fixes signing error in case object name contains symbols [#29]
 

pubspec.yaml

 name: minio
 description: Unofficial MinIO Dart Client SDK that provides simple APIs to access any Amazon S3 compatible object storage server.
-version: 3.0.0
+version: 3.1.0
 homepage: https://github.com/xtyxtyx/minio-dart
 issue_tracker: https://github.com/xtyxtyx/minio-dart/issues
 
 environment:
-  sdk: '>=2.12.0 <3.0.0'
+  sdk: ">=2.12.0 <3.0.0"
 
 dependencies:
   meta: ^1.3.0