build: upgrade to C++23

Meson 1.1.1 and GCC-13 both support C++23 and a sufficient portion of
the standard has been implemented.  Upgrade the build to leverage it.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I4df98991ec483df33af11c9474db4cbed5176e90
diff --git a/meson.build b/meson.build
index e87a9b5..52e330a 100644
--- a/meson.build
+++ b/meson.build
@@ -1,14 +1,14 @@
 project('sdbusplus', 'cpp', 'c',
     default_options: [
       'buildtype=debugoptimized',
-      'cpp_std=c++20',
+      'cpp_std=c++23',
       'warning_level=3',
       'werror=true',
       'tests=' + (meson.is_subproject() ? 'disabled' : 'auto'),
       'examples=' + (meson.is_subproject() ? 'disabled' : 'auto'),
     ],
     version: '1.0.0',
-    meson_version: '>=0.57.0',
+    meson_version: '>=1.1.1',
 )
 
 libsystemd_pkg = dependency('libsystemd')