doc: remove old warning about trigon not being available

README.md

@@ -8,14 +8,6 @@ teaching assistant at the University of Liège.
 _Click the links below to download the pdf directly._ _The slides version
 contains the 'animations', while the handout version is for printing._
 
-**NOTE:** The following links are older versions of the slides. The current one
-require beamertheme-trigon which is not yet available in common docker images
-used for continuous integration/deployment (tis is why the pipeline fails).
-However, if you have an updated version of TexLive or Miktex, you should be able
-to compile the source code and generate the correct version of the slides.
-
-#### AERO0014 - Aerospace Propulsion
-
 #### APRI0004 - Aerospace Design Project
 
 - Blade Element Momentum Theory