Workaround to install cmake on GCP App Engine Standard Environment

I need to install dlib package on App Engine Standard for an application that requires cmake. Below is the error I am facing while the installation.

I tried adding cmake and cmake-setup in requirements.txt but no use.

ERROR: Failed to build one or more wheels
  ERROR: Failed building wheel for dlib
  ----------------------------------------
  
  *******************************************************************
   CMake must be installed to build the following extensions: _dlib_pybind11
  *******************************************************************
  RuntimeError:
      "\n*******************************************************************\n")
 File "/tmp/pip-wheel-hz_z90ap/dlib/setup.py", line 125, in get_cmake_version
      cmake_version = self.get_cmake_version()
    File "/tmp/pip-wheel-hz_z90ap/dlib/setup.py", line 129, in run
      cmd_obj.run()
    File "/opt/python3.7/lib/python3.7/distutils/dist.py", line 985, in run_command
      self.distribution.run_command(command)
    File "/opt/python3.7/lib/python3.7/distutils/cmd.py", line 313, in run_command
      self.run_command(cmd_name)
    File "/opt/python3.7/lib/python3.7/distutils/command/build.py", line 135, in run
      cmd_obj.run()
    File "/opt/python3.7/lib/python3.7/distutils/dist.py", line 985, in run_command
      self.distribution.run_command(command)
    File "/opt/python3.7/lib/python3.7/distutils/cmd.py", line 313, in run_command
      self.run_command('build')
    File "/env/lib/python3.7/site-packages/wheel/bdist_wheel.py", line 290, in run
      cmd_obj.run()
    File "/opt/python3.7/lib/python3.7/distutils/dist.py", line 985, in run_command
      self.run_command(cmd)
    File "/opt/python3.7/lib/python3.7/distutils/dist.py", line 966, in run_commands
      dist.run_commands()
    File "/opt/python3.7/lib/python3.7/distutils/core.py", line 148, in setup
      return distutils.core.setup(**attrs)
    File "/env/lib/python3.7/site-packages/setuptools/__init__.py", line 144, in setup
      'Topic :: Software Development',
    File "/tmp/pip-wheel-hz_z90ap/dlib/setup.py", line 262, in <module>
    File "<string>", line 1, in <module>
  Traceback (most recent call last):
...

Please suggest a fix.