change MIN_boost_version

ubuntu version 20.04 is no longer supported.
The minimum boost version used for freecad is now 1.74 (ubuntu 22.04) https://launchpad.net/ubuntu/jammy/+package/libboost-system-dev

src/Tools/params_utils.py

@@ -81,7 +81,7 @@ def declare_begin(module, header=True):
             f"""
 {trace_comment()}
 #include <Base/Parameter.h>
-{"#include <boost_signals2.hpp>" if signal else ""}
+{"#include <boost/signals2.hpp>" if signal else ""}
 """
         )