bionic-amd64-tf-a-build: add the latest versions of clang/armclang

Add the latest available version of armclang and clang to the list of
required installations.

Change-Id: I3dc4232c29e73fadb6f32dcb8b60a7112817c486
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
1 file changed