build: switch to C++20

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I91a5091c6bd81437e011ea9c89cb4dfa1f1345be
diff --git a/meson.build b/meson.build
index 7f828ac..1dd86c7 100644
--- a/meson.build
+++ b/meson.build
@@ -4,10 +4,11 @@
     default_options: [
         'warning_level=3',
         'werror=true',
-        'cpp_std=c++17'
+        'cpp_std=c++20'
     ],
     license: 'Apache-2.0',
     version: '0.1',
+    meson_version: '>=0.57.0',
 )
 add_project_arguments('-Wno-psabi', language: 'cpp')