Force usage of webkit2gtk-4.1.

Unbreak Boost 1.90 libs
https://github.com/Gnucash/gnucash/commit/14bc748671879d2269fde3edb693b2f02122866c

Index: CMakeLists.txt
--- CMakeLists.txt.orig
+++ CMakeLists.txt
@@ -247,10 +247,7 @@ if (WITH_GNUCASH)
     pkg_check_modules (WEBKIT REQUIRED IMPORTED_TARGET webkitgtk-3.0)
     set(WEBKIT1 1 CACHE INTERNAL "WebKitGtk")
   else()
-    pkg_check_modules (WEBKIT IMPORTED_TARGET webkit2gtk-4.0>=2.14.0)
-    if (NOT WEBKIT_FOUND)
-      pkg_check_modules (WEBKIT REQUIRED IMPORTED_TARGET webkit2gtk-4.1)
-    endif()
+    pkg_check_modules (WEBKIT REQUIRED IMPORTED_TARGET webkit2gtk-4.1)
     set(WEBKIT2 1 CACHE INTERNAL "WebKit2Gtk4")
   endif()
 
@@ -605,11 +602,7 @@ if (Boost_FOUND)
  if (Boost_VERSION VERSION_LESS "1.89.0")
   find_package(Boost 1.67.0  COMPONENTS date_time filesystem locale program_options regex system)
  else()
-  if (Boost_VERSION VERSION_LESS "1.90.0")
-    find_package(Boost 1.67.0  COMPONENTS date_time filesystem locale program_options regex)
-  else()
-    find_package(Boost 1.67.0  COMPONENTS date_time locale program_options regex)
-  endif()
+  find_package(Boost 1.67.0  COMPONENTS date_time filesystem locale program_options regex)
  endif()
 endif()
 
