Require explicit decorator on one arg constructors

We essentially follow this rule already, not relying on implicit
operators, although there are a number of cases where in theory we
could've implicitly constructed an object.

This commit enables the clang-tidy check.

Tested: Code compiles, passes clang-tidy.

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: Ia428463313b075c69614fdb326e8c5c094e7adde
diff --git a/redfish-core/lib/task.hpp b/redfish-core/lib/task.hpp
index b1b1d22..dcad059 100644
--- a/redfish-core/lib/task.hpp
+++ b/redfish-core/lib/task.hpp
@@ -39,7 +39,7 @@
 
 struct Payload
 {
-    Payload(const crow::Request& req) :
+    explicit Payload(const crow::Request& req) :
         targetUri(req.url), httpOperation(req.methodString()),
         httpHeaders(nlohmann::json::array())