add automatic building of conda package

.gitlab-ci.yml

+image: kwant/tinyarray-testing
+
+stages:
+  - test
+  - deploy
+
 python2:
     script:
         - python2 setup.py build_ext -i
         - python2 test_tinyarray.py
+
 python3:
     script:
         - python3 setup.py build_ext -i
@@ -23,3 +30,19 @@ mirror:
       - ORIGIN_URL=$(git config --get remote.origin.url)
       - cd $(mktemp -d); git clone --bare $ORIGIN_URL .
       - for REPO in $REPOS; do git push --mirror $REPO; done
+
+create conda dev package:
+  image: condaforge/linux-anvil
+  stage: deploy
+  only:
+    - master
+  script:
+    - git clone https://gitlab.kwant-project.org/kwant/conda-recipes.git
+    - conda build -c conda-forge --python 3.4 conda-recipes/tinyarray-dev
+    - conda build -c conda-forge --python 3.5 conda-recipes/tinyarray-dev
+    - conda build -c conda-forge --python 3.6 conda-recipes/tinyarray-dev
+    - mv /opt/conda/conda-bld/linux-64/tinyarray-dev*.tar.bz2 .
+    - anaconda --token=$ANACONDA_TOKEN upload --force tinyarray-dev*tar.bz2
+  artifacts:
+    paths:
+      - tinyarray-dev*.tar.bz2