Escape &,> in --set and --build-arg

Feature Request: Escape the & > passed in --build-arg and --set options, eg

acb build --build-arg arg1=a&b  => arg1=a\&b
acb exec --set key1=a>b => key1=a\>b

Maybe it's just safe to escape all chars passed in --build-arg and --set, eg \a\r\g\1\=\a\&\b

I had the same issue if it contains { as it errors saying there is no closing braket