Change shim.cloudready to shim.chromeos

We're not CloudReady anymore, so make the names a little clearer.

BUG=b:195942249
TEST=`make build && make copy && make dump-sbat`

Change-Id: I4a18f4dbd495ba7433dbbe0365aecaea57a8f47b

sbat.csv

diff --git a/sbat.csv b/sbat.csv
index 7143d30..6f5ec34 100644
--- a/sbat.csv
+++ b/sbat.csv
@@ -1,4 +1,4 @@
 sbat,1,SBAT Version,sbat,1,https://github.com/rhboot/shim/blob/main/SBAT.md
 shim,1,UEFI shim,shim,1,https://github.com/rhboot/shim
-shim.cloudready,1,CloudReady,shim,15.4,https://chromium.googlesource.com/external/github.com/neverware/shim-build/
+shim.chromeos,1,Chrome OS,shim,15.4,https://chromium.googlesource.com/external/github.com/neverware/shim-build/