Enabled includeLocalVariables option in Sentry

ref https://linear.app/tryghost/issue/SLO-92/enable-extra-sentry-integrations
refs https://docs.sentry.io/platforms/javascript/guides/node/configuration/options/#include-local-variables

- this will capture the local stack variables when producing a stack
  trace, which would be super useful when debugging

ghost/core/core/shared/sentry.js

@@ -97,6 +97,7 @@ if (sentryConfig && !sentryConfig.disabled) {
         release: 'ghost@' + version,
         environment: environment,
         maxValueLength: 1000,
+        includeLocalVariables: true,
         integrations: [
             Sentry.extraErrorDataIntegration()
         ],