Merge branch 'update-either' of https://github.com/hoc081098/rxdart_ext into update-either

Author: hoc081098

.github/workflows/dart.yml

@@ -19,8 +19,9 @@ jobs:
 
     strategy:
       matrix:
-        sdk: [ beta, stable, 2.17.0, 2.15.0, 2.12.0 ]
+#         sdk: [ beta, stable, 2.17.0, 2.15.0, 2.12.0 ]
 #         rxdart: [ 0.27.5, 0.27.6, 0.27.7, not_override ]
+        sdk: [ beta, stable, 3.0.0 ]
         rxdart: [ not_override ]
 
     steps: