Enable readability-uppercase-literal-suffix

We only had a few violations of this;  Fix them and enable the check.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I159e774fd0169a91a092218ec8dc896ba9edebf4
diff --git a/http/routing.hpp b/http/routing.hpp
index 8fd4558..8c4fa2f 100644
--- a/http/routing.hpp
+++ b/http/routing.hpp
@@ -688,7 +688,7 @@
     {
         for (size_t x : node->paramChildrens)
         {
-            if (x == 0u)
+            if (x == 0U)
             {
                 continue;
             }