[IMP] web_tree_dynamic_colored_field: Update README.rst (#899)

Use more than one color condition

web_tree_dynamic_colored_field/README.rst

@@ -65,6 +65,26 @@ Usage
     </field>
     ...
 
+* If you want to use more than one color, you can split the attributes using ';':
+
+.. code::
+
+   options='{"fg_color": "red:red_color == True; green:green_color == True"}'
+
+Example:
+
+.. code:: xml
+
+   ...
+    <field name="arch" type="xml">
+        <tree string="View name">
+            ...
+            <field name="name" options='{"fg_color": "red:red_color == True; green:green_color == True"}'/>
+            ...
+        </tree>
+    </field>
+    ...
+
     With this example, the content of the field named `my_color` will be used to
     populate the `my_color` CSS value. Use a function field to return whichever
     color you want depending on the other record values. Note that this