Updating GIT repo URL for Verilator

Verilator now moved their repo to GitHub

source/VexiiRiscv/HowToUse/index.rst

@@ -34,7 +34,7 @@ On debian :
 
     # Verilator (optional, for simulations)
     sudo apt-get install git make autoconf g++ flex bison help2man
-    git clone http://git.veripool.org/git/verilator   # Only first time
+    git clone https://github.com/verilator/verilator
     unsetenv VERILATOR_ROOT  # For csh; ignore error if on bash
     unset VERILATOR_ROOT  # For bash
     cd verilator