Test against fluent.syntax 0.13 instead of 0.12

Author: spookylukey

.travis.yml

@@ -10,7 +10,7 @@ python:
   - "nightly"
 env:
   global:
-    - FLUENT_RUNTIME_DEFAULT_DEPS="fluent.syntax==0.12.0 attrs==19.1.0 babel==2.6.0 pytz==2018.9 six==1.12.0"
+    - FLUENT_RUNTIME_DEFAULT_DEPS="fluent.syntax==0.13.0 attrs==19.1.0 babel==2.6.0 pytz==2018.9 six==1.12.0"
     - FLUENT_SYNTAX_DEFAULT_DEPS="six"
   matrix:
     - PACKAGE=fluent.syntax

fluent.runtime/tox.ini

@@ -1,14 +1,14 @@
 # This config is for local testing. It should be duplicated into .travis.yml
 [tox]
-envlist = {py27, py35, py36, py37, pypy, pypy3}-syntax0.12, py36-syntax0.10, latest
+envlist = {py27, py35, py36, py37, pypy, pypy3}-syntax0.13, py36-syntax0.10, latest
 skipsdist=True
 
 [testenv]
 setenv =
     PYTHONPATH = {toxinidir}
 deps =
      syntax0.10: fluent.syntax==0.10.0
-     syntax0.12: fluent.syntax==0.12.0
+     syntax0.13: fluent.syntax==0.13.0
      attrs==19.1.0
      babel==2.6.0
      pytz==2018.9