Not able to build dexseq/v1.30.0/Dockerfile

[cmball1]

Not able to build the Dockerfile dexseq/v1.30.0/Dockerfile:

Collecting pysam
  Downloading https://files.pythonhosted.org/packages/25/7e/098753acbdac54ace0c6dc1f8a74b54c8028ab73fb027f6a4215487d1fea/pysam-0.15.4.tar.gz (1.6MB)
    Complete output from command python setup.py egg_info:
    # pysam: no cython available - using pre-compiled C
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-build-mVBXzi/pysam/setup.py", line 193, in <module>
        .format(fn))
    ValueError: no cython installed, but can not find pysam/libchtslib.c.Make sure that cython is installed when building from the repository
    
    ----------------------------------------
Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-build-mVBXzi/pysam/
The command '/bin/sh -c apt-get update     && apt-get install -y --no-install-recommends         python-dev         python-pip     && pip install setuptools     && pip install wheel     && pip install pysam     && pip install HTSeq     && apt-get autoremove     && rm -rf /var/lib/apt/lists/*' returned a non-zero code: 1

See GitHub Actions run for more info: https://github.com/RTIInternational/biocloud_docker_tools/runs/465555645?check_suite_focus=true