web_widget_bokeh_chart: pin bokeh version

setup/web_widget_bokeh_chart/setup.py

@@ -2,5 +2,11 @@ import setuptools
 
 setuptools.setup(
     setup_requires=['setuptools-odoo'],
-    odoo_addon=True,
+    odoo_addon={
+        "external_dependencies_override": {
+            "python": {
+                "bokeh": "bokeh==1.1.0",
+            },
+        }
+    }
 )