use std::format instead of fmt::format

The std::format is sufficient for the uses in this repository except
for in one file (override_fan_target.cpp, since P2286 isn't supported
by GCC yet).  Switch to std::format whenever possible.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: Ib2576fb530a4d7ce238e1b0bd95b40b476ec2107
diff --git a/control/json/actions/count_state_target.cpp b/control/json/actions/count_state_target.cpp
index dcbd70d..b2a900b 100644
--- a/control/json/actions/count_state_target.cpp
+++ b/control/json/actions/count_state_target.cpp
@@ -20,10 +20,10 @@
 #include "action.hpp"
 #include "group.hpp"
 
-#include <fmt/format.h>
-
 #include <nlohmann/json.hpp>
 
+#include <format>
+
 namespace phosphor::fan::control::json
 {