Slash "/" in branchname break build

[MattiasJa]

Branch name is "user/featureXYZ".
Part of build script that fails :

gh-pages-multi deploy "-v" "-s" "docs/storybook" "-t" "user/featureXYZ" "--no-history"
2020-06-25T15:39:18.229Z gh-pages-multi deploy docs/storybook to git@git.comp.se:SKV/skv_webkit.git:gh-pages/user/featureXYZ
2020-06-25T15:39:18.236Z gh-pages-multi Run command: git ls-remote --heads git@git.comp.se:SKV/skv_webkit.git gh-pages
2020-06-25T15:39:18.444Z gh-pages-multi output= a5a4b2f556a6ce7983127c977f8c44027273038c refs/heads/gh-pages
2020-06-25T15:39:18.444Z gh-pages-multi branch gh-pages exists, clone it.
2020-06-25T15:39:18.444Z gh-pages-multi Run command: git clone --single-branch -b gh-pages git@git.rsv.se:SKV/skv_webkit.git /tmp/tmp-3262uFWltnRHxNzt
2020-06-25T15:39:29.711Z gh-pages-multi user/featureXYZ does not exist yet
2020-06-25T15:39:29.711Z gh-pages-multi replace the directory user/featureXYZ with new content from docs/storybook
[ { Error: ENOENT: no such file or directory, mkdir '/tmp/tmp-3262uFWltnRHxNzt/user/featureXYZ'
errno: -2,
code: 'ENOENT',
syscall: 'mkdir',
path:
'/tmp/tmp-3262uFWltnRHxNzt/user/featureXYZ' } ]
npm ERR! code ELIFECYCLE