Capitalize "AS" in dockerfile

Dockerfile.in

@@ -41,7 +41,7 @@
 #############################################################################
 # First we prepare the image that we want, regardless of build layers.
 #############################################################################
-FROM {ARG_FROM} as base
+FROM {ARG_FROM} AS base
 
 # When building, we can pass a unique value (e.g. `date +%s`) for this arg,
 # which will force a rebuild from here (by invalidating docker's cache).
@@ -72,7 +72,7 @@ RUN /stage_binaries.sh -o {ARG_STAGING} \
 	-f /tmp
 RUN ln -s /bin/bash {ARG_STAGING}/bin/sh # Not sure why this is not set up automatically
 
-FROM scratch as intermediate
+FROM scratch AS intermediate
 
 # Docker doesn't do vars in COPY, so we can't use a regular ARG.
 COPY --from=base {ARG_STAGING} /