Make README notes more consistent

README.md

@@ -58,14 +58,14 @@ npm install --save mongoose-beautiful-unique-validation
 
 Starting from version 7.0.0, this module only supports Mongoose 4.11.4 and upper. Usage with older Mongoose versions might work, but is not supported. If we need to use outdated versions of Mongoose, use older versions of this package as documented in the table below.
 
-_Note that only security fixes will be backported to older versions._
-
 | This package’s version | Supported Mongoose versions |
 | ----------------------:|:--------------------------- |
 |                      7 | ≥ 4.11.4                    |
 |                   5, 6 | ≥ 4.5.0                     |
 |             1, 2, 3, 4 | ≥ 4.0.0                     |
 
+> **Note**: Only security fixes will be backported to older versions.
+
 ### Supported versions of Node
 
 This module currently supports Node.js 4, 5, 6, 7 and 8. If you find a bug while using one of these versions, please [fill a bug report!](https://github.com/matteodelabre/mongoose-beautiful-unique-validation/issues/new)