Object.assign is not defined for older browsers (e.g. IE 11)

[pencilcheck]

subscriptions-transport-ws/src/helpers.ts

Line 16 in 0e81e9e

return Object.assign(networkInterface, {

Getting error when running inside older browsers using the library.

[mistic]

Maybe we can move from Object.assign to the lodash.cloneDeep. What do u think @DxCx @Urigo @NeoPhi ?

[NeoPhi]

We should pull in an use the 'object-assign' library. This is the one that react-apollo uses. We definitely shouldn't switch to a deep cloning.

[mistic]

Lol ( @NeoPhi @DxCx ) I was almost sleeping when I wrote this! What I meant was lodash.assign and not cloneDeep. As react-apollo already uses the 'object-assign' maybe we can also use it.