Test on Python 3.5 as well (#388)

Author: asvetlov

.azure-pipelines/stage-test.yml

@@ -6,6 +6,10 @@ stages:
   - job:
     strategy:
       matrix:
+        Py35-Cython-Linux:
+          python.version: '3.5'
+          no_extensions: ''
+          image: 'ubuntu-latest'
         Py36-Cython-Linux:
           python.version: '3.6'
           no_extensions: ''
@@ -18,6 +22,10 @@ stages:
           python.version: '3.8'
           no_extensions: ''
           image: 'ubuntu-latest'
+        Py35-Pure-Linux:
+          python.version: '3.5'
+          no_extensions: 'Y'
+          image: 'ubuntu-latest'
         Py36-Pure-Linux:
           python.version: '3.6'
           no_extensions: 'Y'
@@ -34,6 +42,10 @@ stages:
 #          python.version: 'pypy3'
 #          no_extensions: 'Y'
 #          image: 'ubuntu-latest'
+        Py35-Cython-Win:
+          python.version: '3.5'
+          no_extensions: ''
+          image: 'vs2017-win2016'
         Py36-Cython-Win:
           python.version: '3.6'
           no_extensions: ''
@@ -46,6 +58,10 @@ stages:
           python.version: '3.8'
           no_extensions: ''
           image: 'windows-latest'
+        Py35-Cython-Mac:
+          python.version: '3.5'
+          no_extensions: ''
+          image: 'macos-latest'
         Py36-Cython-Mac:
           python.version: '3.6'
           no_extensions: ''