The file building.{md,html} indicates the required minimum version of Xcode to
use. When the required minimum version of Clang was updated to 13
([JDK-8325878](https://bugs.openjdk.org/browse/JDK-8325878)), the minimum Xcode
version was not updated. It should now be Xcode 13.0, rather than 8.
-------------
Commit messages:
- 8327493: Update minimum Xcode version in docs
Changes: https://git.openjdk.org/jdk/pull/18483/files
Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=18483&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8327493
Stats: 2 lines in 2 files changed: 0 ins; 0 del; 2 mod
Patch: https://git.openjdk.org/jdk/pull/18483.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/18483/head:pull/18483
PR: https://git.openjdk.org/jdk/pull/18483
