Change flux version to 2.1.1
Change flux version to 2.1.1

It was previously pinned to 2.0.3 in https://github.com/vector-im/riot-web/commit/5bab440a1
but only here and not in react-sdk, meaning that react-sdk was
still using the latest, at least in develop builds, however
react-sdk now uses utils which requires 2.1, so pin to 2.1.1
everywhere for sanity.

vector-im/vector-web,vector-im/vector-web,martindale/vector,vector-im/riot-web,vector-im/vector-web,vector-im/riot-web,vector-im/riot-web,vector-im/riot-web,vector-im/vector-web,vector-im/vector-web,martindale/vector,vector-im/riot-web,vector-im/riot-web