Fix babel warnings building docker

[grzanka]

 => => # babel-preset-react-app is part of the create-react-app project, which                                                                                                         
 => => # is not maintianed anymore. It is thus unlikely that this bug will                                                                                                             
 => => # ever be fixed. Add "@babel/plugin-proposal-private-property-in-object" to                                                                                                     
 => => # your devDependencies to work around this error. This will make this message                                                                                                   
 => => # go away