chruby: unknown Ruby: ruby-2.6.1

.ruby-version

2.6.1

config.yaml

# .circleci/config.yaml
version: 2
jobs:
  build-and-test:
    macos:
      xcode: "10.1.0"
    working_directory: /Users/distiller/project
    environment:
      FL_OUTPUT_DIR: output
      FASTLANE_LANE: test
    shell: /bin/bash --login -eo pipefail
    steps:
      - checkout
      - restore_cache:
          key: 1-gems-{{ checksum "Gemfile.lock" }}
      - run: bundle check || bundle install --path vendor/bundle
      - save_cache:
          key: 1-gems-{{ checksum "Gemfile.lock" }}
          paths:
            - vendor/bundle
            - Pods
      - run:
          name: fastlane
          command: bundle exec fastlane $FASTLANE_LANE
      - store_artifacts:
          path: output
      - store_test_results:
          path: output/scan

workflows:
  version: 2
  build-test-adhoc:
    jobs:
      - build-and-test

Fastfile

# fastlane/Fastfile
default_platform :ios

platform :ios do
  before_all do
    setup_circle_ci
  end

  desc "Runs all the tests"
  lane :test do
    scan
  end

  desc "Ad-hoc build"
  lane :adhoc do
    match(type: "adhoc")
    gym(export_method: "ad-hoc")
  end
end

Gemfile

source 'https://rubygems.org'
ruby '2.6.1'

gem 'cocoapods'
gem 'fastlane'

Gemfile.lock

GEM
  remote: https://rubygems.org/
  specs:
    #[...]

PLATFORMS
  ruby

DEPENDENCIES
  #[...]

RUBY VERSION
   ruby 2.6.1p33

BUNDLED WITH
   1.17.2