Update CHANGELOG.md

+## [3.12.1]	
+- Remove spaces whitespaces from dart files	
+
+## [3.12.0]	
+- Added BottomSheet Duration && Export SingleGetTickerProvider (@unacorbatanegra)	
+- Improve docs from dependencies management (@ngxingyu)	
+- Fix unknownRoute with null Custom Transition (@marcosfons)	
+- Optimize capitalize method (@zl910627)	
+- Added Chinese documentation (@idootop)	
+- Added TextDirection property on GetMaterialApp to improve RTL layout (@justkawal)	
+- Remove unnecessary files on git (@nipodemos)	
+- Fix tags on Get.create() and GetWidget() (@roipeker)	
+- Update mockito dependency on getTests	
+- Added GetStatelessWidget, a StatelessWidget base to GetWidget with lifecycle control of controllers. Note: It's a base class, you don't need change to use it or change your GetView, GetWidget StatelessWidget to It.
+
 ## [3.11.1]
 - Fix docs