Remove Python 3.9 dev build from travis, it's not needed

.travis.yml

@@ -25,9 +25,10 @@ matrix:
     # For now ignore pypy, there are so many issues that we don't really need
     # to run it.
     #- python: pypy
-    - python: 3.9-dev
-      env:
-        - JEDI_TEST_ENVIRONMENT=38
+    # The 3.9 dev build does not seem to be available end 2019.
+    #- python: 3.9-dev
+    #  env:
+    #    - JEDI_TEST_ENVIRONMENT=38
 install:
     - pip install --quiet tox-travis
 script: