update README.md.

Signed-off-by: 葛峻恺 <202115006@mail.sdu.edu.cn>

README.md

@@ -26,8 +26,6 @@ GPR-SIDL-inv/
 
 ├── field_data/                # Used to store field data for inversion
 
-├── gprMax/                    # Forward modeling package developed by the University of Edinburgh
-
 ├── IMG/                       # Used for storing data processing and inversion result graphs
 
 ├── impulse/                   # Used to store simulated and measured source wavelet files