examples: Add missing dependency on glib-2.0

It has previously been implicitly pulled in by libsysprof-capture, but
that will change in future.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Helps: #40

examples/meson.build

@@ -1,3 +1,3 @@
 app = executable('example-app', 'app.c',
-  dependencies: [libsysprof_capture_dep],
+  dependencies: [dependency('glib-2.0'), libsysprof_capture_dep],
 )