Upgrade Dart SDK constraints (#114)

* Migrate platform_interface to pigeon 0.2.1

* Format

* Fix Analysis

* Update SDK version constraints

+## 0.1.0+1
+
+* Changed Dart SDK constraint to `>=2.12.0`.
+
 ## 0.1.0
 
 * Bumped to stable null safety release.

 name: wakelock_macos
 description: >-2
   macOS platform implementation of the wakelock_platform_interface for the wakelock plugin.
-version: 0.1.0
+version: 0.1.0+1
 homepage: https://github.com/creativecreatorormaybenot/wakelock/tree/master/wakelock_macos
 
 environment:
-  sdk: '>=2.12.0-259.9.beta <3.0.0'
+  sdk: '>=2.12.0 <3.0.0'
   flutter: '>=1.24.0-0'
 
 dependencies:

+## 0.2.1+1
+
+* Changed Dart SDK constraint to `>=2.12.0`.
+
 ## 0.2.1
 
 * Migrated to pigeon `0.2.1`, which fixes deprecated usage of `setMockMessageHandler`.

@@ -2,12 +2,12 @@ name: wakelock_platform_interface
 description: >-2
   A common platform interface for the wakelock plugin used by the different platform
   implementations.
-version: 0.2.1
+version: 0.2.1+1
 homepage: >-2
   https://github.com/creativecreatorormaybenot/wakelock/tree/master/wakelock_platform_interface
 
 environment:
-  sdk: '>=2.12.0-259.9.beta <3.0.0'
+  sdk: '>=2.12.0 <3.0.0'
 
 dependencies:
   flutter:

+## 0.2.0+1
+
+* Changed Dart SDK constraint to `>=2.12.0`.
+
 ## 0.2.0
 
 * Bumped to stable null safety release.

 name: wakelock_web
 description: Web platform implementation of the wakelock_platform_interface for the wakelock plugin.
-version: 0.2.0
+version: 0.2.0+1
 homepage: https://github.com/creativecreatorormaybenot/wakelock/tree/master/wakelock_web
 
 environment:
-  sdk: '>=2.12.0-259.9.beta <3.0.0'
+  sdk: '>=2.12.0 <3.0.0'
   flutter: '>=1.24.0-0'
 
 dependencies: