docs: update docs around auth0 jwk_url support

[praveenweb]

Auth0 has fixed a bug which prevented Hasura from using their rotating keys.

The docs around configuring HASURA_GRAPHQL_JWT_SECRET for Auth0 needs to be updated.

Places where this content needs to be updated:

• https://hasura.io/docs/1.0/graphql/manual/auth/authentication/jwt.html#example-jwk-url
• https://hasura.io/docs/1.0/graphql/manual/guides/integrations/auth0-jwt.html#configure-hasura-to-use-auth0-keys
• https://hasura.io/jwt-config/

[marionschleifer]

We should also update the docs to use always use accessToken since this was recommended by Auth0.

[sanderhahn]

In the https://hasura.io/docs/1.0/graphql/manual/guides/integrations/auth0-jwt.html user sync snippet the configuration object can be used to store the url and admin secret outside of the sourcecode. https://auth0.com/docs/rules/guides/configuration

[seanparkross]

We're closing this issue. The docs for auth have recently been updated. We'd really like to hear your thoughts on those new docs in our Discord. If you feel that this issue has been closed in error please comment again and we will reopen.