fix: NEXT_PUBLIC variable access (#94)

Ensure that the `NEXT_PUBLIC_` variable is inlined during builds.

https://nextjs.org/docs/app/building-your-application/configuring/environment-variables#bundling-environment-variables-for-the-browser

(The above link specifically talks about the browser, but the inlining of NEXT_PUBLIC variables also applies to middleware).

src/env-variables.ts

@@ -11,7 +11,7 @@ const WORKOS_COOKIE_DOMAIN = getEnvVariable('WORKOS_COOKIE_DOMAIN');
 const WORKOS_COOKIE_MAX_AGE = getEnvVariable('WORKOS_COOKIE_MAX_AGE');
 const WORKOS_COOKIE_NAME = getEnvVariable('WORKOS_COOKIE_NAME');
 const WORKOS_COOKIE_PASSWORD = getEnvVariable('WORKOS_COOKIE_PASSWORD') ?? '';
-const WORKOS_REDIRECT_URI = getEnvVariable('NEXT_PUBLIC_WORKOS_REDIRECT_URI') ?? '';
+const WORKOS_REDIRECT_URI = process.env.NEXT_PUBLIC_WORKOS_REDIRECT_URI ?? '';
 
 export {
   WORKOS_API_HOSTNAME,