Add CI config for the extension

.gitlab-ci.yml

+tests-stable:
+    image: octobus/ci-py2-hgext3rd
+    script:
+        - hg pull -R /ci/repos/mercurial/ --rev stable
+        - hg -R /ci/repos/mercurial/ update stable
+        - apt-get update && apt-get install -y libgraphviz-dev graphviz pkg-config
+        - pip install .
+        - (cd tests; /ci/repos/mercurial/tests/run-tests.py --color=always)
+tests-default:
+    image: octobus/ci-py2-hgext3rd
+    script:
+        - hg pull -R /ci/repos/mercurial/ --rev default
+        - hg -R /ci/repos/mercurial/ update default
+        - apt-get update && apt-get install -y libgraphviz-dev graphviz pkg-config
+        - pip install .
+        - (cd tests; /ci/repos/mercurial/tests/run-tests.py --color=always)
+
+tests-5.2:
+    image: octobus/ci-py2-hgext3rd:hg-5.2
+    script:
+        - apt-get update && apt-get install -y libgraphviz-dev graphviz pkg-config
+        - pip install .
+        - (cd tests; /ci/repos/mercurial/tests/run-tests.py --color=always)
+
+tests-5.1:
+    image: octobus/ci-py2-hgext3rd:hg-5.1
+    script:
+        - apt-get update && apt-get install -y libgraphviz-dev graphviz pkg-config
+        - pip install .
+        - (cd tests; /ci/repos/mercurial/tests/run-tests.py --color=always)
+
+tests-5.0:
+    image: octobus/ci-py2-hgext3rd:hg-5.0
+    script:
+        - apt-get update && apt-get install -y libgraphviz-dev graphviz pkg-config
+        - pip install .
+        - (cd tests; /ci/repos/mercurial/tests/run-tests.py --color=always)
+
+tests-4.9:
+    image: octobus/ci-py2-hgext3rd:hg-4.9
+    script:
+        - apt-get update && apt-get install -y libgraphviz-dev graphviz pkg-config
+        - pip install .
+        - (cd tests; /ci/repos/mercurial/tests/run-tests.py --color=always)
+
+tests-4.8:
+    image: octobus/ci-py2-hgext3rd:hg-4.8
+    script:
+        - apt-get update && apt-get install -y libgraphviz-dev graphviz pkg-config
+        - pip install .
+        - (cd tests; /ci/repos/mercurial/tests/run-tests.py --color=always)
+
+tests-4.7:
+    image: octobus/ci-py2-hgext3rd:hg-4.7
+    script:
+        - apt-get update && apt-get install -y libgraphviz-dev graphviz pkg-config
+        - pip install .
+        - (cd tests; /ci/repos/mercurial/tests/run-tests.py --color=always)
+
+tests-4.6:
+    image: octobus/ci-py2-hgext3rd:hg-4.6
+    script:
+        - apt-get update && apt-get install -y libgraphviz-dev graphviz pkg-config
+        - pip install .
+        - (cd tests; /ci/repos/mercurial/tests/run-tests.py --color=always)