Add armv6l to the ARM replacements list for docker executor helper image

Merged Tomasz Maczukin requested to merge fix/support-armv6l-with-docker-correctly into master

What does this MR do?

Adds armv6l architecture to arm replacements list for docker executor helper image.

Why was this MR needed?

Please read #2038 (closed) for a reference.

Are there points in the code the reviewer needs to double check?

Does this MR meet the acceptance criteria?

  • Documentation created/updated
  • Tests
    • Added for this feature/bug
    • All builds are passing
  • Branch has no merge conflicts with master (if you do - rebase it please)

What are the relevant issue numbers?

Closes #2038 (closed)