stop shipping python 2 wheel to pypi

travis' dpl command seems to be broken for python 2:

travis-ci/dpl#1232

Work around this by just publishing sdist and py3 wheel. Python 2
users will just have to use the sdist.

.travis.yml

@@ -14,18 +14,19 @@ _python_template: &_python_template
   before_install: cd client/
   install: pip install -e .[test]
   script: py.test
-  deploy:
-    provider: pypi
-    edge: true
-    username: "__token__"
-    password: $PYPI_TOKEN1$PYPI_TOKEN2
-    distributions: "sdist bdist_wheel"
-    skip_existing: true
-    skip_cleanup: true
-    on:
-      branch: master
-      tags: true
-      repo: planetlabs/datalake
+
+_deploy_template: &_deploy
+  provider: pypi
+  edge: true
+  username: "__token__"
+  password: $PYPI_TOKEN1$PYPI_TOKEN2
+  distributions: "sdist bdist_wheel"
+  skip_existing: true
+  skip_cleanup: true
+  on:
+    branch: master
+    tags: true
+    repo: planetlabs/datalake
 
 jobs:
   include:
@@ -36,6 +37,8 @@ jobs:
   - <<: *_python_template
     name: py35 bare
     python: 3.5
+    deploy:
+      <<: *_deploy
   - <<: *_python_template
     name: py27 with extras
     python: 2.7
@@ -44,6 +47,8 @@ jobs:
     name: py35 with extras
     python: 3.5
     install: pip install -e .[test,queuable,sentry]
+    deploy:
+      <<: *_deploy
   - dist: bionic
     name: docker
     stage: test