docker-image: add --pull to build command

docker does not automatically make sure the latest base images are
fetche before building in image. This causes old base images to be used
even when newer ones are available.

Add `--pull` to the build command to make sure it fetches new images
before using them.
1 job for master in 24 seconds
Status Job ID Name Coverage
  Verify
passed #51248
docker-alpine
lint

00:00:24