SC3036 false positive on ash (In Dash, echo flags besides -n are not supported)

[felipecrs]

For bugs

• Rule Id: SC3036
• My shellcheck version: 0.10.0
• The rule's wiki page does not already cover this (https://shellcheck.net/wiki/SC3036)
• I tried on https://www.shellcheck.net/ and verified that this is still a problem on the latest commit

Here's a snippet or screenshot that shows the problem:

# shellcheck shell=ash

echo -e "\nhi\nthere\nyou"

Here's what shellcheck currently says:

echo -e "\nhi\nthere\nyou"
     ^-- [SC3036](https://www.shellcheck.net/wiki/SC3036) (error): In dash, echo flags besides -n not supported.

Here's what I wanted or expected to see:

Nothing, as this is supported:

$ docker run --rm -it alpine ash -c 'echo -e "\nhi\nthere\nyou"'

hi
there
you

$ docker run --rm -it busybox sh -c 'echo -e "\nhi\nthere\nyou"

hi
there
you