Updated changelog and bumped version number (#137)

* chore: update changelog and bump version number

* docs: add min version sdk update

Author: HamdaanAliQuatil

CHANGELOG.md

@@ -1,3 +1,8 @@
+# 0.5.7
+* Added compatibility for AGP 8.4.
+* Improved API documentation for ECDH.
+* Bumped minimum Android SDK/ API level to 21, dropping support for Android 4 and below.
+
 # 0.5.6
 * Disable LTO on Android to fix [#80](https://github.com/google/webcrypto.dart/issues/80).
 * Migrate to `dart:js_interop` to ensure [wasm compatibility](https://dart.dev/interop/js-interop/package-web#package-web-vs-dart-html).

pubspec.yaml

@@ -13,7 +13,7 @@
 # limitations under the License.
 
 name: webcrypto
-version: 0.5.6
+version: 0.5.7
 description: Cross-platform implementation of Web Cryptography APIs for Flutter.
 repository: https://github.com/google/webcrypto.dart