Add Tensorflow update site to installation instructions

Updated installation instructions to include Tensorflow update site.

Author: tinevez

_pages/plugins/trackmate/detectors/trackmate-stardist.md

@@ -8,11 +8,18 @@ This page describes a detector module for [TrackMate](/plugins/trackmate/index)
 
 ## Installation
 
-You need to subscribe to the **CSBDeep** update site and to the **StarDist** update site first, then to the **TrackMate-StarDist** update site:
+You need to subscribe to several update sites:
+- the **CSBDeep** update site,
+- the **Tensorflow** update site,
+- to the **StarDist** update site,
+- then to the **TrackMate-StarDist** update site:
 
 The CSBDeep update site:
 ![Subscribe to the CSBDeep update site](/media/plugins/trackmate/trackmate-stardist-install-csbdeep.png)
 
+The Tensorflow update site:
+![Subscribe to the Tensorflow update site](/media/plugins/trackmate/trackmate-stardist-install-tensorflow.png)
+
 The StarDist update site:
 ![Subscribe to the StarDist update site](/media/plugins/trackmate/trackmate-stardist-install-stardist.png)