Fix syntax error in :firestore/set effect example

[olivergg]

Fix the :firestore/set` effect example in the README.md docs (the map contained an odd number of forms, which is invalid)

[gabrielsimoes]

Looks good to me. If you can, please also correct the same error here:

https://github.com/deg/re-frame-firebase/blob/216595bab8e392caee1233a6480495d610b7a215/src/com/degel/re_frame_firebase.cljs#L209

[olivergg]

Looks good to me. If you can, please also correct the same error here:

re-frame-firebase/src/com/degel/re_frame_firebase.cljs

Line 209 in 216595b

;;; {:firestore/set :path [:my-collection "my-document"]

Done.

[deg]

Thanks!