Gitlab CI Potrubí se nezdaří, protože ruby vydání (Ruby nainstalován)

Snažím se nastavit CI na Gitlab. Mám problém. Vypadá to, že běžec se pracuje dobře, ale pokaždé, když se snažím spustit potrubí se nezdaří s následující chybová zpráva :

Running with gitlab-runner 14.4.0 (4b9e985a)
  on local-runner g_SbFiLZ
Resolving secrets
00:00
Preparing the "shell" executor
00:00
Using Shell executor...
Preparing environment
00:00
Running on GU33...
Getting source from Git repository
00:02
Fetching changes with git depth set to 50...
Reinitialized existing Git repository in C:/Users/xxx/GitLab-Runner/builds/g_SbFiLZ/0/xxx/xxx/.git/
Checking out f4fb6ec9 as main...
git-lfs/2.11.0 (GitHub; windows amd64; go 1.14.2; git 48b28d97)
Skipping Git submodules setup
Executing "step_script" stage of the job script
00:01
$ gem install bundler
gem : The term 'gem' is not recognized as the name of a cmdlet, function, script file, or operable program. Check the s
pelling of the name, or if a path was included, verify that the path is correct and try again.
At C:\WINDOWS\TEMP\build_script461193448\script.ps1:225 char:1
+ gem install bundler
+ ~~~
    + CategoryInfo          : ObjectNotFound: (gem:String) [], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException
 
Cleaning up project directory and file based variables
00:00
ERROR: Job failed: exit status 1

Mám Ruby nainstalováno a nastaveno správně. Můžu běžet gem příkazy lokálně. Runner je také nastavit lokálně, takže jsem opravdu dont pochopit problém. Tady je můj gitlab-ci.yml :

stages:
  - prepare
  - build
  - test
  - ui-test

variables:
  LC_ALL: "en_US.UTF-8"
  LANG: "en_US.UTF-8"

.setup_bundler: &setup_bundler |
  gem install bundler
  bundle config
  bundle install

.setup: &setup
  - *setup_bundler

prepare_project:
  stage: prepare
  script:
    *setup
  cache:
    key:
      files:
        - Gemfile.lock
    paths:
      - vendor
  artifacts:
    name: "Bundle_${CI_BUILD_NAME}_${CI_BUILD_REF_NAME}_${CI_BUILD_ID}"
    expire_in: 1 day
    paths:
      - vendor
    when: always
  when: on_success
  tags:
    - android

build:
  stage: build
  script:
    - bundle exec fastlane build
  dependencies:
    - prepare_project
  tags:
    - android

test:
  stage: test
  script:
    - bundle exec fastlane tests
  dependencies:
    - prepare_project
  tags:
    - android

ui-test:
  stage: ui-test
  script:
    - bundle exec fastlane ui_tests
  dependencies:
    - prepare_project
  tags:
    - android

Nějaké nápady, pelase ?