v8.0.0-beta

• Query parameters service_id and plan_id are made available as FetchInstanceDetails for Fetch Instance and FetchBindingsDetails for Fetch Binding endpoints. Thank you @NickyMateev!(#138 #147)
• Add plan_updateable attribute to ServicePlan struct. Thank you @ksegun! (#139)
• Add support for X-Broker-API-Request-Identity header. X-Broker-API-Request-Identity is exposed in the context as requestIdentity and is returned as a header in the response. Thank you @qbarrand! (#148 #121)
• Update dependencies