CI: use conditional deploy stage

.travis.yml

@@ -4,9 +4,9 @@ sudo: false
 language: python
 
 python:
-  - "3.4"
-  - "3.5"
-  - "3.6"
+  - 3.4
+  - 3.5
+  - 3.6
 
 install:
   - pip3 install .
@@ -22,13 +22,16 @@ script:
 jobs:
   include:
     - stage: Deploy
+      if: tag =~ v[[:digit:]]*.[[:digit:]]*.[[:digit:]]
+      python: 3.6
+      install: true
+      before_script: true
+      script: true
       deploy:
         provider: pypi
         user: mhinz
         password:
           secure: "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"
-        on:
-          tags: true
 
 notifications:
   email: