Update C++ version CFLAGS as Verilator requires C++14 or newer

[saahm]

Closes #

Context, Motivation & Description

I stumbled on this when I used a Docker container with newer Verilator versions, SpinalHDL would not be able to build the Verilator simulations as an Error about the C++ Version (c++11 instead c++14) occurs.

In file included from /usr/share/verilator/include/verilated_dpi.cpp:30:
/usr/share/verilator/include/verilatedos.h:271:3: error: #error "Verilator requires a C++14 or newer compiler"
  271 | # error "Verilator requires a C++14 or newer compiler"
      |   ^~~~~
In file included from /usr/share/verilator/include/verilated.h:42,
                 from ./VMurax.h:11,
                 from ../main.cpp:1:
/usr/share/verilator/include/verilatedos.h:271:3: error: #error "Verilator requires a C++14 or newer compiler"
  271 | # error "Verilator requires a C++14 or newer compiler"
      |   ^~~~~

This commit should at least fix it for now.

Is there any further checks I need to do or what I can do to help this?

Impact on code generation

Checklist

• [ ] Unit tests were added
• [ ] API changes are or will be documented:
  • using Scaladoc comments: /** */?
  • on RTD?
  • thanks to a new tracking issue on RTD?

[Dolu1990]

Thanks ^^