tidy: Replace deprecated C headers with the corresponding C++ header.

This code was pointed out by clang-tidy's "deprecated headers" check.
Changes made by clang-tidy.

https://clang.llvm.org/extra/clang-tidy/checks/modernize-deprecated-headers.html

mythtv/libs/libmythtv/tv_play.cpp

@@ -2,13 +2,13 @@
 #include "tv_play.h"
 
 #include <algorithm>
+#include <cassert>
 #include <chrono> // for milliseconds
 #include <cmath>
 #include <cstdarg>
 #include <cstdint>
 #include <cstdlib>
 #include <thread> // for sleep_for
-#include <assert.h>
 
 using namespace std;