add JL to authors (#56)

AUTHORS.md

@@ -6,9 +6,16 @@ T8code.jl is written by
 
 hereby called the "T8code Authors".
 
+# Contributors
+
+The following people contributed major additions or modifications to T8code.jl:
+
+- [Joshua Lampert](https://github.com/JoshuaLampert).
+
 The software is an adapted fork of P4est.jl which is maintained by
 
+- [Joshua Lampert](https://github.com/JoshuaLampert)
 - [Michael Schlottke-Lakemper](https://lakemper.eu)
-- [Hendrik Ranocha](https://ranocha.de).
+- [Hendrik Ranocha](https://ranocha.de)
 
 hereby called "contributors".

README.md

@@ -198,10 +198,12 @@ Julia `v1.9` (or newer) is more widely established in the community.
 ## Authors
 
 T8code.jl is mainly maintained by [Johannes Markert](https://jmark.de) (German
-Aerospace Center (DLR), Germany).  It is an adapted fork from
-[P4est.jl](https://github.com/trixi-framework/P4est.jl) maintained by [Michael
-Schlottke-Lakemper](https://lakemper.eu) (RWTH Aachen University, Germany) and
-[Hendrik Ranocha](https://ranocha.de) (University of Hamburg, Germany).
+Aerospace Center (DLR), Germany) and [Joshua Lampert](https://github.com/JoshuaLampert)
+(University of Hamburg, Germany). It is an adapted fork from
+[P4est.jl](https://github.com/trixi-framework/P4est.jl) maintained by [Joshua
+Lampert](https://github.com/JoshuaLampert), [Michael Schlottke-Lakemper](https://lakemper.eu)
+(RWTH Aachen University, Germany), and [Hendrik Ranocha](https://ranocha.de)
+(Johannes Gutenberg University Mainz, Germany).
 
 The [`t8code`](https://github.com/DLR-AMR/t8code) library itself is written by
 Johannes Holke and Carsten Burstedde, and others.