[C++] Remove unused header.

Author: denizevrenci

sbe-tool/src/main/java/uk/co/real_logic/sbe/generation/cpp/CppGenerator.java

@@ -937,7 +937,6 @@ private static CharSequence generateFileHeader(
  "#endif\n" +
  "#include <string.h>\n" +
  "#include <stdint.h>\n" +
- "#include <limits.h>\n" +
  "#include <stdexcept>\n" +
  "#include <cstdint>\n" +
  "#include <limits>\n\n" +