Release react 5.3.0

[kealjones-wk]

The latest release of react includes:

• https://github.com/cleandart/react-dart/pull/241/commits/fb5fdab5fbf28d1e8027cb9075f6b7d6015eba2f Unpin the react-redux JS dependency to allow versions 7.1.1 and higher.
• https://github.com/cleandart/react-dart/pull/241/commits/0c3ba95391f32b3d1a102d35799f46bf5942e108 Run over_react tests as part of the CI process to prevent another situation where changing JS dependencies regressed tightly coupled libs like over_react_redux (like the one that required the 5.2.1 hotfix).
• https://github.com/cleandart/react-dart/pull/242 Implement the StrictMode Component

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FYA @greglittlefield-wf @kealjones-wk @joebingham-wk

[greglittlefield-wf]

+10