oe-selftest: cpp-example meson version warning

Newer versions of meson throw a warning if newer features are used
without explicit declaration of the required meson version.

(From OE-Core rev: 92d1c2343f9c7afe4ad627b3059f2e9556084d5d)

Signed-off-by: Adrian Freihofer <adrian.freihofer@siemens.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta-selftest/recipes-test/cpp/files/meson.build

@@ -6,7 +6,8 @@
 
 project('meson-example', 'cpp',
     version: '1.0.0',
-    default_options: ['cpp_std=c++17']
+    default_options: ['cpp_std=c++17'],
+    meson_version: '>=1.1.0'
     )
 
 jsoncdep = dependency('json-c')