[SEBA-512]

Fix xosgenx's handling of optional/required modifiers in relation to
the null and blank options, which was nondeterministic depending on the
order of items iterated over in the options dictionary.

Don't allow 'Null' booleans

Change-Id: I3f21180ec11c7e43794c04ebe479d50c11f6271c
diff --git a/containers/chameleon/Dockerfile.chameleon b/containers/chameleon/Dockerfile.chameleon
index 90ae1e1..33f64b0 100644
--- a/containers/chameleon/Dockerfile.chameleon
+++ b/containers/chameleon/Dockerfile.chameleon
@@ -13,8 +13,7 @@
 # limitations under the License.
 
 # xosproject/chameleon
-
-FROM xosproject/xos-base:2.2.3
+FROM xosproject/xos-base:2.2.4
 
 # xos-base already has protoc and dependencies installed