add readme link + notebook package installation if needed

Author: foca13

README.md

@@ -113,7 +113,7 @@ These are examples of how DeepTrack2 can be used on real datasets:
 
   Training a fully connected neural network to identify handwritten digits using MNIST dataset.
 
-- DTEx212 **Single Particle Tracking** <!-- **[Single Particle Tracking](https://github.com/DeepTrackAI/DeepTrack2/blob/develop/tutorials/2-examples/DTEx212_single_particle_tracking.ipynb)** <a href="https://colab.research.google.com/github/DeepTrackAI/DeepTrack2/blob/develop/tutorials/2-examples/DTEx212_single_particle_tracking.ipynb"><img src="https://colab.research.google.com/assets/colab-badge.svg"></a> -->
+- DTEx212 **[Single Particle Tracking](https://github.com/DeepTrackAI/DeepTrack2/blob/develop/tutorials/2-examples/DTEx212_single_particle_tracking.ipynb)** <a href="https://colab.research.google.com/github/DeepTrackAI/DeepTrack2/blob/develop/tutorials/2-examples/DTEx212_single_particle_tracking.ipynb"><img src="https://colab.research.google.com/assets/colab-badge.svg"></a>
 
   Tracks experimental videos of a single particle.
 
@@ -122,9 +122,6 @@ These are examples of how DeepTrack2 can be used on real datasets:
     <img width="300" src=/assets/SPT-ideal.gif?raw=true>
     <img width="300" src=/assets/SPT-noisy.gif?raw=true>
     <br/>
-    <a href="https://colab.research.google.com/github/DeepTrackAI/DeepTrack2/blob/develop/tutorials/2-examples/DTEx212_single_particle_tracking.ipynb">
-      <img src="https://colab.research.google.com/assets/colab-badge.svg">
-    </a>
     <a href="https://doi.org/10.1364/OPTICA.6.000506" alt="DeepTrack article">
       <img src="https://img.shields.io/badge/article-10.1364/OPTICA.6.000506-blue">
     </a>