sdbusplus: update meson to v8 format

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Id1a2086530218d1e578554501d29552a5f307846
diff --git a/gen/meson.build b/gen/meson.build
index b550c79..c63d829 100644
--- a/gen/meson.build
+++ b/gen/meson.build
@@ -5,10 +5,10 @@
     check: true,
 ).stdout().strip().split('\n')[0]
 
-if sdbuspp_gen_meson_ver != 'sdbus++-gen-meson version 7'
+if sdbuspp_gen_meson_ver != 'sdbus++-gen-meson version 8'
     warning('Generated meson files from wrong version of sdbus++-gen-meson.')
     warning(
-        'Expected "sdbus++-gen-meson version 7", got:',
+        'Expected "sdbus++-gen-meson version 8", got:',
         sdbuspp_gen_meson_ver
     )
 endif