MINIFICPP-2823 Fix build with gcc 16

Fixes:
  extensions/systemd/libwrapper/LibWrapper.h:38:31: error: 'uint64_t' has not been declared
   38 |   virtual int getRealtimeUsec(uint64_t* usec_out) noexcept = 0;
      |                               ^~~~~~~~

Closes #2194

Signed-off-by: Marton Szasz <szaszm@apache.org>

Author: Mingli Yu

core-framework/include/core/RepositoryMetricsSource.h

@@ -20,6 +20,7 @@
 
 #include <string>
 #include <optional>
+#include <cstdint>
 
 #include "minifi-cpp/core/RepositoryMetricsSource.h"
 

extensions/systemd/libwrapper/LibWrapper.h

@@ -19,6 +19,7 @@
 #pragma once
 
 #include <memory>
+#include <cstdint>
 
 #include "../Common.h"
 #include "minifi-cpp/utils/gsl.h"

minifi-api/include/minifi-cpp/core/RepositoryMetricsSource.h

@@ -18,6 +18,7 @@
 
 #pragma once
 
+#include <cstdint>
 #include <string>
 #include <optional>