message: Use JWT_KEY_FILE_PATH if available
  While the README had you set the JWT_KEY_FILE_PATH, it was being ignored
  when the code was loading.
  This fixes that to use the environment variable and fallback on a
  default path if needed.
diff: @@ -7,9 +7,9 @@ import { castIntEnv, castStringArrayEnv } from '../utils'
  export const {
  JWT_KEY,
  JWT_ALGORITHM = 'RS256',
  - JWT_CLAIMS_NAMESPACE = 'https://hasura.io/jwt/claims'
  -} = process.env
  -export const JWT_KEY_FILE_PATH = path.resolve(process.env.PWD || '.', 'custom/keys/private.pem')
  + JWT_CLAIMS_NAMESPACE = 'https://hasura.io/jwt/claims',
  + JWT_KEY_FILE_PATH = path.resolve(process.env.PWD || '.', 'custom/keys/private.pem'),
  +} = process.env;
  export const JWT_EXPIRES_IN = castIntEnv('JWT_EXPIRES_IN', 15)
  export const JWT_REFRESH_EXPIRES_IN = castIntEnv('JWT_REFRESH_EXPIRES_IN', 43200)
  export const JWT_CUSTOM_FIELDS = castStringArrayEnv('JWT_CUSTOM_FIELDS')
  