Add interceptors

[xiaoqiang1999]

We would really like to use redaxios but interceptors are quite important for us.
Would love to be able to add interceptors in redaxios.

[icithis]

This has been requested for some time - over two years - and a PR has been sitting for about that long. Not sure why we're still waiting.

#9

[nickchomey]

The lack of interceptors is unfortunately a dealbreaker for me as well. But, the real axios seems like it'll get a fetch adapter soon enough. axios/axios#5146