Update bootstrap documentation to require JDK 11, not JDK 8
@@ -194,7 +194,7 @@ You can also build Bazel from scratch, without using an existing Bazel binary.
* **C++ build toolchain**
-* **JDK.** Versions 8 and 11 are supported.
+* **JDK.** Version 11 is required.
* **Python**. Versions 2 and 3 are supported, installing one of them is
enough.
