refactor: Recommend using restricted API key (#23)

* refactor: Rename API key param

BREAKING CHANGE: Now called stripe_key

* docs: Update README

Add note recommending restricted key usage

* docs: Additional README context

README.md

@@ -18,12 +18,13 @@ yarn add next-stripe@beta
 
 Create a `[...nextstripe].js` catch-all route in your project's `pages/api/stripe` directory.
 
+> ⚠️ PLEASE NOTE: It is recommended you use a [restricted key](https://stripe.com/docs/keys#limit-access) with limited API access with this library. These keys can be created and configured with the required access in the Stripe Dashboard.
+
 ```js
 import NextStripe from 'next-stripe'
 
 export default NextStripe({
-  secret_key: process.env.STRIPE_SECRET_KEY
-})
+  stripe_key: process.env.STRIPE_RESTRICTED_KEY
 ```
 
 ## Usage

src/server/routes/confirm/payment-intent.js

@@ -2,7 +2,7 @@ import Stripe from 'stripe'
 
 export default async function confirmPaymentIntent(req, res, options) {
   try {
-    const stripe = new Stripe(options.secret_key)
+    const stripe = new Stripe(options.stripe_key)
 
     const { id, body } = req.body
 

src/server/routes/create/billing-portal-session.js

@@ -2,7 +2,7 @@ import Stripe from 'stripe'
 
 export default async function createBillingPortalSession(req, res, options) {
   try {
-    const stripe = new Stripe(options.secret_key)
+    const stripe = new Stripe(options.stripe_key)
 
     const session = await stripe.billingPortal.sessions.create(req.body)
 

src/server/routes/create/checkout-session.js

@@ -2,7 +2,7 @@ import Stripe from 'stripe'
 
 export default async function createCheckoutSession(req, res, options) {
   try {
-    const stripe = new Stripe(options.secret_key)
+    const stripe = new Stripe(options.stripe_key)
 
     const session = await stripe.checkout.sessions.create(req.body)
 

src/server/routes/create/payment-intent.js

@@ -2,7 +2,7 @@ import Stripe from 'stripe'
 
 export default async function createPaymentIntent(req, res, options) {
   try {
-    const stripe = new Stripe(options.secret_key)
+    const stripe = new Stripe(options.stripe_key)
 
     const paymentIntent = await stripe.paymentIntents.create(req.body)
 

src/server/routes/retrieve/payment-intent.js

@@ -2,7 +2,7 @@ import Stripe from 'stripe'
 
 export default async function retrievePaymentIntent(req, res, options) {
   try {
-    const stripe = new Stripe(options.secret_key)
+    const stripe = new Stripe(options.stripe_key)
 
     const paymentIntent = await stripe.paymentIntents.retrieve(req.body.id)
 

src/server/routes/update/payment-intent.js

@@ -2,7 +2,7 @@ import Stripe from 'stripe'
 
 export default async function updatePaymentIntent(req, res, options) {
   try {
-    const stripe = new Stripe(options.secret_key)
+    const stripe = new Stripe(options.stripe_key)
 
     const { id, body } = req.body