Validator does not count arguments correctly for ADD and COPY instructions written in JSON

[rcjsuen]

The following Dockerfile can be built just fine but the validator will create warnings because it thinks there is only one argument in the two instructions since there are no spaces in the JSON.

FROM alpine
ADD ["t1.txt","t2.txt"]
COPY ["t1.txt","t2.txt"]

$ dockerfile-utils lint Dockerfile
Line: 2
ADD ["t1.txt","t2.txt"]
    ^^^^^^^^^^^^^^^^^^^
Error: ADD requires at least two arguments

Line: 3
COPY ["t1.txt","t2.txt"]
     ^^^^^^^^^^^^^^^^^^^
Error: COPY requires at least two arguments

$ docker build .
Sending build context to Docker daemon  1.696MB
Step 1/3 : FROM alpine
 ---> 3fd9065eaf02
Step 2/3 : ADD ["t1.txt","t2.txt"]
 ---> 5b13022208ff
Step 3/3 : COPY ["t1.txt","t2.txt"]
 ---> 057ec728c238
Successfully built 057ec728c238