fix: include <string> in binary_buffer.h for fix macos builds

[chenrui333]

include <string> to fix some compile issue as below

  In file included from /tmp/diamond-20250125-4855-7vw53/diamond-2.1.11/src/basic/packed_transcript.h:21:
  /tmp/diamond-20250125-4855-7vw53/diamond-2.1.11/src/util/binary_buffer.h:93:8: error: implicit instantiation of undefined template 'std::basic_string<char>'
                                  dst.push_back(c);
                                     ^
  /Library/Developer/CommandLineTools/SDKs/MacOSX13.sdk/usr/include/c++/v1/iosfwd:248:32: note: template is declared here
      class _LIBCPP_TEMPLATE_VIS basic_string;
                                 ^

relates to Homebrew/homebrew-core#205487

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