Fix a typo in the CI script

1 job for master in 28 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
failed #127
build

00:00:28

 
Name Stage Failure
failed
build Build
HEAD is now at df184df Add a simple CI file for build 9.0
From https://forge.tedomum.net/tedomum/odoo
df184df..063eaa3 master -> origin/master
Checking out 063eaa3c as master...
Skipping Git submodules setup
$ docker build --build-arg ODOO_VERSION=9.0 --tag $CI_REGISTY_IMAGE:9.0 .
invalid argument ":9.0" for "-t, --tag" flag: invalid reference format
See 'docker build --help'.
ERROR: Job failed: exit code 125