Decimals in duration incorrectly flagged as an error

[rcjsuen]

FROM scratch
HEALTHCHECK --timeout=5s.1ms CMD ls

$ docker build .
Sending build context to Docker daemon  1.693MB
Step 1/2 : FROM scratch
 --->
Step 2/2 : HEALTHCHECK --timeout=5s.1ms CMD ls
 ---> Running in 3af4f3acc567
 ---> 22f68f4e91b1
Removing intermediate container 3af4f3acc567
Successfully built 22f68f4e91b1

It seems like the parsing of a flag's duration isn't quite right.

$ dockerfile-utils lint Dockerfile
Line: 2
HEALTHCHECK --timeout=5s.1ms CMD ls
                      ^^^^^^
Error: time: unknown unit . in duration 5s.1ms