Emulator Support

[charliegucci]

We want to use your code, any chance you can change the url to be more flexible?

const setDocRes: any = await fetch(`https://firestore.googleapis.com/v1beta1/projects/${typedEnv.FIREBASE_REST_PROJECT_ID}/databases/${finalDb}/documents/${docPath}${mergeAppend}`, {
        method: 'PATCH',
        headers: generateFirebaseReqHeaders(finalDb),
        body: JSON.stringify({
            fields: dumbGoogleObject
        })
    })