build: switch to C++20

1. Updated to C++20
2. Limit meson version >= 0.58.0
3. Added the default buildtype to debugoptimized

Signed-off-by: George Liu <liuxiwei@inspur.com>
Change-Id: I1318c1aabdbeb285c1bea83b6820c878d5152c8a
diff --git a/meson.build b/meson.build
index fdec677..b672b29 100755
--- a/meson.build
+++ b/meson.build
@@ -1,10 +1,12 @@
 project(
     'biosconfig-manager',
     'cpp',
+    meson_version: '>=0.58.0',
     default_options: [
         'warning_level=3',
         'werror=true',
-        'cpp_std=c++17'
+        'cpp_std=c++20',
+        'buildtype=debugoptimized'
     ],
     license: 'Apache-2.0',
     version: '1.0',