python version isssue in building open3d from source

### Checklist

- [X] I have searched for [similar issues](https://github.com/isl-org/Open3D/issues).
- [X] For Python issues, I have tested with the [latest development wheel](http://www.open3d.org/docs/latest/getting_started.html#development-version-pip).
- [X] I have checked the [release documentation](http://www.open3d.org/docs/release/) and the [latest documentation](http://www.open3d.org/docs/latest/) (for `master` branch).

### Steps to reproduce the issue

I am trying to install the open3d from source.
Ran into issues with python version during build.

### Error message

```shell
-- CMAKE_BUILD_TYPE is set to Release.
-- Downloading third-party dependencies to /home/user/Gopi/Open3D/3rdparty_downloads
CMake Deprecation Warning at CMakeLists.txt:189 (cmake_policy):
The OLD behavior for policy CMP0072 will be removed from a future version
of CMake.

The cmake-policies(7) manual explains that the OLD behaviors of all
policies are deprecated and that a policy should be set to OLD only under
specific short-term circumstances. Projects should be ported to the NEW
behavior and not rely on setting a policy to OLD.

-- Open3D 0.17.0+61671310a
-- Could NOT find Python3 (missing: Development Development.Module Development.Embed) (found suitable version "3.9.5", minimum required is "3.6")
CMake Error at CMakeLists.txt:333 (message):
BUILD_PYTHON_MODULE=ON requires Python >= 3.6. Please ensure it is in
PATH.

-- Configuring incomplete, errors occurred!
```

### Open3D, Python and System information

```markdown
- Operating system: Ubuntu 20
- Python version: Python 3.8
- Cmake version: 3.27
- System architecture: jetson
- Is this a remote workstation?:no
- How did you install Open3D?:build from source
- Compiler version (if built from source): gcc 9.4.0
```

### Additional information

_No response_