Upgrading from JSS 13.0 to JSS 14.0

1. Update peer dependencies version.
2. Update all @sitecore-jss/* packages to the latest 14.x version.
3. React application:

• Check all usages of withSitecoreContext:
  • If you extend ComponentConsumerProps using withSitecoreContext<T>, so component will have set of props that extend ComponentConsumerProps interface, not implement only ComponentConsumerProps as it was.
• Check all usages of Placeholder component:
  • You can return ReactElement in functions: render, renderEach, renderEmpty
  • Check renderEach function implementation, now it has correct declaration (component: React.ReactNode, index: number): React.ComponentClass<any> | React.SFC<any> | React.ReactNode