Merge pull request #3 from Workiva/update_notice

CPLAT-6223 Add dart-lang/sse project to NOTICE

Author: rmconsole7-wk

NOTICE

@@ -24,4 +24,8 @@ Dart-lang build software: https://github.com/dart-lang/build
 Copyright ©2016 Dart project authors.
 Licensed under the BSD 3-Clause License: https://github.com/dart-lang/build/blob/master/LICENSE
 
+Dart-lang sse software: https://github.com/dart-lang/sse
+Copyright ©2019 Dart project authors.
+Licensed under the BSD 3-Clause License: https://github.com/dart-lang/sse/blob/master/LICENSE
+
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