* test(zsh): add test for C-r with foreign commands
* ci: make docker command configurable via variable
Allows using alternative container runtimes, e.g., DOCKER=podman make docker-test
* test(zsh): use unique histfile for foreign commands test
* test(zsh): use multi select in foreign test
Enable inserting multiple history commands. To disable, set `--no-multi`
through `$FZF_CTRL_R_OPTS`.
Also, remove the usage of `become` action, to avoid leaving behind
temporary files.
Co-authored-by: Junegunn Choi <junegunn.c@gmail.com>
