Environment installation fails for Crawler/Kinetics

[LukasHedegaard]

Using conda 4.8.2 on macOS Catalina, the

conda env create -f environment.yml

command as described in https://github.com/activitynet/ActivityNet/tree/master/Crawler/Kinetics fails with the error:

Collecting package metadata (repodata.json): done
Solving environment: failed

ResolvePackageNotFound: 
  - menpo::ffmpeg==3.1.3=0
  - pytz==2017.2=py27_0
  - setuptools==27.2.0=py27_0
  - python-dateutil==2.6.0=py27_0
  - wheel==0.29.0=py27_0
  - sqlite==3.13.0=0
  - mkl==2017.0.1=0
  - joblib==0.9.4=py27_0
  - openssl==1.0.2k=1
  - pip==9.0.1=py27_1
  - tk==8.5.18=0
  - pandas==0.19.2=np112py27_1
  - python==2.7.13=0
  - readline==6.2=2
  - zlib==1.2.8=3
  - numpy==1.12.1=py27_0
  - six==1.10.0=py27_0

[LukasHedegaard]

Fix proposed in #73