Pin upper versions of dependencies.

Author: rnixx

CHANGES.rst

@@ -5,6 +5,9 @@ Changes
 1.2.3 (unreleased)
 ------------------
 
+- Pin upper versions of dependencies.
+  [rnix]
+
 - Fix ``Node.treerepr`` if mapping raises an exception on ``__getitem__``.
   [rnix]
 

setup.py

@@ -46,8 +46,8 @@ def read_file(name):
     include_package_data=True,
     zip_safe=True,
     install_requires=[
-        'odict>=1.9.0',
-        'plumber>=1.5',
+        'odict>=1.9.0,<2.0.0',
+        'plumber>=1.5,<2.0.0',
         'setuptools',
         'zope.component',
         'zope.deferredimport',