make header1 to header2

Author: TimoK93

README.md

@@ -19,7 +19,7 @@ Detailed descriptions of the metrics can be found in the [paper](...).
 
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-# Features at a Glance
+## Features at a Glance
 
 - **Validation**: Check if the tracking results are correctly formatted.
 - **Evaluation**: Evaluate the tracking results with respect to the ground truth using CTC, MotChallenge, and CHOTA metrics.