[build] install scripts/srt-ffplay in the bin directory

We don't need to use CMAKE_INSTALL_BINDIR which is not defined when
GNUInstallDirs is not used. Using "TYPE BIN" will have the same result
and will automatically pick the same as CMAKE_INSTALL_BINDIR.

https://cmake.org/cmake/help/latest/command/install.html#installing-files

CMakeLists.txt

@@ -1339,7 +1339,7 @@ if (ENABLE_UNITTESTS AND ENABLE_CXX11)
 endif()
 
 
-install(PROGRAMS scripts/srt-ffplay DESTINATION ${CMAKE_INSTALL_BINDIR})
+install(PROGRAMS TYPE BIN scripts/srt-ffplay)
 
 
 if (DEFINED SRT_EXTRA_APPS_INC)