Add dh_make dependency

[bafu]

Execute dlmodel2deb on clear system without dh-make will get errors below:

$ ./dlmodel2deb <source-package-dirpath>
/bin/sh: 1: dh_make: not found
/bin/sh: 1: cd: can't cd to debian
rm: cannot remove '*ex': No such file or directory
rm: cannot remove '*EX': No such file or directory
rm: cannot remove 'README.*': No such file or directory
...
Traceback (most recent call last):
  File "./dlmodel2deb", line 72, in <module>
    main()
  File "./dlmodel2deb", line 67, in main
    create_install(work_dirpath)
  File "./dlmodel2deb", line 24, in create_install
    with open('debian/install', 'w') as f:
FileNotFoundError: [Errno 2] No such file or directory: 'debian/install'