utils/docker-run: allow interactive use

Without -i, the container cannot be used interactively. Allow using it as
in:

  $ ./utils/docker-run
  + exec docker run -v /home/ceresoli/devel/buildroot:/home/br-user -it registry.gitlab.com/buildroot.org/buildroot/base:20220206.1756
  br-user@1e9508a4ccbb:~$ ls
  arch  board  boot  CHANGES  Config.in  Config.in.legacy  configs  COPYING  DEVELOPERS  docs  fs  linux	Makefile  Makefile.legacy  output  package  README  support  system  toolchain	utils
  br-user@1e9508a4ccbb:~$

Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

utils/docker-run

@@ -7,4 +7,4 @@ IMAGE=$(grep ^image: "${MAIN_DIR}/.gitlab-ci.yml" | \
         sed -e 's,^image: ,,g' | sed -e 's,\$CI_REGISTRY,registry.gitlab.com,g')
 
 set -x
-exec docker run -v "${MAIN_DIR}:/home/br-user" -t "${IMAGE}" "$@"
+exec docker run -v "${MAIN_DIR}:/home/br-user" -it "${IMAGE}" "$@"