Merge pull request circleci#3666 from circleci/xcode

Xcode 11 beta 6

Author: michelle-luna

jekyll/_cci2/testing-ios.md

@@ -29,7 +29,7 @@ We announce the availability of new macOS containers in the [annoucements sectio
 
 The currently available Xcode versions are:
 
-* `11.0.0`: Xcode 11.0 (Beta 5) (Build 11M362v) [installed software](https://circle-macos-docs.s3.amazonaws.com/image-manifest/build-954/index.html)
+* `11.0.0`: Xcode 11.0 (Beta 6) (Build 11M392q) [installed software](https://circle-macos-docs.s3.amazonaws.com/image-manifest/build-999/index.html)
 * `10.3.0`: Xcode 10.3 (Build 10G8) [installed software](https://circle-macos-docs.s3.amazonaws.com/image-manifest/build-903/index.html)
 * `10.2.1`: Xcode 10.2.1 (Build 10E1001) [installed software]( https://circle-macos-docs.s3.amazonaws.com/image-manifest/build-594/index.html)
 * `10.1.0`: Xcode 10.1 (Build 10B61) [installed software](https://circle-macos-docs.s3.amazonaws.com/image-manifest/build-474/index.html)