Remove Kotlin Binder link that does not work and replace with GNU Octave example

Author: SylvainCorlay

assets/try/GNUOctave.png

@@ -50,19 +50,19 @@
       description: How to use Jupyter with C++
       src: try/Cpp.svg
       alt: C++ logo - Launch C++ demo Binder
-      url: https://mybinder.org/v2/gh/QuantStack/xeus-cling/stable?filepath=notebooks/xcpp.ipynb
+      url: https://mybinder.org/v2/gh/jupyter-xeus/xeus-cling/stable?filepath=notebooks/xcpp.ipynb
 
     - title: Julia
       description: How to use Jupyter with Julia
       src: try/julia.svg
       alt: Julia logo - Launch Julia demo Binder
       url: https://mybinder.org/v2/gh/binder-examples/demo-julia/HEAD?filepath=demo.ipynb
 
-    - title: Kotlin
-      description: How to use Jupyter with Kotlin
-      src: try/kotlin.svg
-      alt: Kotlin logo - Launch Kotlin demo Binder
-      url: https://mybinder.org/v2/gh/Kotlin/dataframe/master?filepath=examples/jupyter-notebooks/titanic/Titanic.ipynb
+    - title: GNU Octave
+      description: How to use Jupyter with GNU Octave
+      src: try/GNUOctave.png
+      alt: GNU Octave logo - Launch GNU Octave demo Binder
+      url: https://mybinder.org/v2/gh/jupyter-xeus/xeus-octave/stable?urlpath=/lab/tree/notebooks/xeus-octave.ipynb
 
     - title: R
       description: How to use Jupyter with R