fix(@schematics/angular): update latest known versions

Author: filipesilva

packages/schematics/angular/utility/latest-versions.ts

@@ -8,11 +8,11 @@
 
 export const latestVersions = {
   // These versions should be kept up to date with latest Angular peer dependencies.
-  Angular: '^6.0.0-rc.1',
-  RxJs: '^6.0.0-rc.0',
-  ZoneJs: '^0.8.24',
+  Angular: '^6.0.0-rc.5',
+  RxJs: '^6.0.0',
+  ZoneJs: '^0.8.26',
   TypeScript: '~2.7.2',
   // The versions below must be manually updated when making a new devkit release.
-  DevkitBuildAngular: '~0.5.0',
-  DevkitBuildNgPackagr: '~0.5.0',
+  DevkitBuildAngular: '~0.5.8',
+  DevkitBuildNgPackagr: '~0.5.8',
 };