Explain rosbags dependency in README

README.md

@@ -82,6 +82,8 @@ PyQt5 will give you the enhanced GUI for plot figures from the "*Qt5Agg*" matplo
 
 Some ROS-related features require a ROS installation, see [here](http://www.ros.org/). We are testing this package with ROS Noetic and Iron. Previous versions (`<= 1.12.0`) work with Melodic, Kinetic and Indigo.
 
+*Note:* reading ROS bag files works also without a ROS installation thanks to the great [rosbags](https://pypi.org/project/rosbags/) package that is installed together with evo. This allows you also to read ROS 1 & 2 bags even if you don't have one of those ROS distros installed. (except for reading `/tf` topics, because there we need the buffer implementation from ROS)
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 ## Command Line Interface