Update .gitlab-ci.yml to make the CI work

.gitlab-ci.yml

-image: debian:testing
+image: ghdl/vunit:gcc-master
+
+run_tests:
+  script: python3 ./testbench/run.py
+
+## OLD CI script below  
+#image: debian:testing
 #service:
 #  - python:latest
-
-build:
-  stage: build
-  before_script:
-    - apt-get update
-    - apt-get install -y git make colormake
-    - apt-get install -y gcc-7 gnat-7 gcc gnat
-    - apt-get install -y llvm-4.0 llvm-4.0-dev llvm-4.0-tools llvm
-    - apt-get install -y clang-4.0 clang
-    - apt-get install -y zlib1g-dev libedit-dev
-    - apt-get install -y python3 python3-pip
+#
+#build:
+#  stage: build
+#  before_script:
+#    - apt-get update
+#    - apt-get install -y git make colormake
+#    - apt-get install -y gcc-7 gnat-7 gcc gnat
+#    - apt-get install -y llvm-4.0 llvm-4.0-dev llvm-4.0-tools llvm
+#    - apt-get install -y clang-4.0 clang
+#    - apt-get install -y zlib1g-dev libedit-dev
+#    - apt-get install -y python3 python3-pip
 #    - ./tools/GitLab-CI/grc.setup.sh
-    - ./tools/GitLab-CI/ghdl.setup.sh
-    - pip3 install -r ./tools/GitLab-CI/requirements.txt
-  script:
-    - echo "build"
-    - export PATH=$PATH:./ghdl/bin
-    - export VUNIT_SIMULATOR=ghdl
-    - python3 ./testbench/run.py -k
+#    - ./tools/GitLab-CI/ghdl.setup.sh
+#    - pip3 install -r ./tools/GitLab-CI/requirements.txt
+#  script:
+#    - echo "build"
+#    - export PATH=$PATH:./ghdl/bin
+#    - export VUNIT_SIMULATOR=ghdl
+#    - python3 ./testbench/run.py -k
 #  artifacts:
 #    paths:
 #      - mybinary
-
+#
 ## run tests using the binary built before
 #test:
 #  stage: test