small change readme

Author: simongravelle

README.md

@@ -9,20 +9,20 @@ The files include:
 - the detailed solutions to the exercises,
 - Python scripts for generating structures and analyzing data.
 
-### Main repository ###
+### Main repository
 
 Find [here](https://github.com/lammpstutorials/lammpstutorials.github.io)
 the main repository for LAMMPS tutorial.
 
-### About me & Contact ###
+### About me & Contact
 
 I am a computer physicist in soft matter and fluids at interfaces. You can 
 find more information on my [personal webpage](https://simongravelle.github.io/).
 
 See the [contact page](https://lammpstutorials.github.io/sphinx/build/html/non-tutorials/contact-me.html). 
 You can report issues here on Github, or send me an [email](https://simongravelle.github.io/). Your feedback is always appreciated.
 
-### License & Acknowledgments ###
+### License & Acknowledgments
 
 All the LAMMPS inputs/data/parameter files and Python scripts are released under the 
 GNU general public license v3.0.
@@ -31,4 +31,4 @@ This project has received funding from the European
 Union's Horizon 2020 research and innovation programme
 under the Marie Skłodowska-Curie grant agreement No 101065060.
 
-![Acknowledgments-logos](https://raw.githubusercontent.com/simongravelle/credits/1c44b5ae76a33c5bbbd33a54243365c6abdc24b2/cnrs-uga-liphy-msca.png)
+![Acknowledgments-logos](https://raw.githubusercontent.com/simongravelle/credits/1c44b5ae76a33c5bbbd33a54243365c6abdc24b2/cnrs-uga-liphy-msca.png)