redux-form: added missing label?: string field
redux-form: added missing label?: string field

This field seems to be missing,
according to https://redux-form.com/7.1.2/examples/syncvalidation/ it should be available
AgentME/DefinitelyTyped,dsebastien/DefinitelyTyped,chrootsu/DefinitelyTyped,georgemarshall/DefinitelyTyped,alexdresko/DefinitelyTyped,zuzusik/DefinitelyTyped,AgentME/DefinitelyTyped,one-pieces/DefinitelyTyped,zuzusik/DefinitelyTyped,aciccarello/DefinitelyTyped,AgentME/DefinitelyTyped,rolandzwaga/DefinitelyTyped,borisyankov/DefinitelyTyped,AbraaoAlves/DefinitelyTyped,magny/DefinitelyTyped,dsebastien/DefinitelyTyped,borisyankov/DefinitelyTyped,georgemarshall/DefinitelyTyped,arusakov/DefinitelyTyped,aciccarello/DefinitelyTyped,zuzusik/DefinitelyTyped,AbraaoAlves/DefinitelyTyped,magny/DefinitelyTyped,alexdresko/DefinitelyTyped,arusakov/DefinitelyTyped,mcliment/DefinitelyTyped,AgentME/DefinitelyTyped,rolandzwaga/DefinitelyTyped,georgemarshall/DefinitelyTyped,aciccarello/DefinitelyTyped,AbraaoAlves/DefinitelyTyped,georgemarshall/DefinitelyTyped,arusakov/DefinitelyTyped,markogresak/DefinitelyTyped,benliddicott/DefinitelyTyped,laurentiustamate94/DefinitelyTyped,chrootsu/DefinitelyTyped