Update .gitlab-ci.yml file with build and test

stages:          # List of stages for jobs, and their order of execution

  - build

  - test

build-job:       # This job runs in the build stage, which runs first.

  stage: build

  script:

    - echo "Compiling libcdict..."

    - meson setup --buildtype release builddir

    - ninja -C builddir

    - echo "Compile of libcdict complete."

unit-test-job:   # This job runs in the test stage.

  stage: test    # It only starts when the job in the build stage completes successfully.

  script:

    - echo "Running libcdict tests..."

    - ./builddir/cdict-config --tests

    - echo "Test of libcdict complete."