Upgrade to latest wazimap version

[divyamani1]

Fixes #84

Major changes:

• Upgrade to Python 3.7
• Use Python 3.7 bullseye docker image (current stable Debian release)
• Upgrade libgdal-dev to 3.2.2+dfsg-2+deb11u1
• Upgrade wazimap to 2.1.2
• Upgrade GDAL to 3.2.2.1

[pratimakandel]

PR looks good! However when deploying using Docker, I'm running into

Running setup.py install for ecdsa: finished with status 'error'
  error: subprocess-exited-with-error

  × Running setup.py install for ecdsa did not run successfully.
  │ exit code: 1
  ╰─> [3 lines of output]
      running build_ext
      UPDATING build/lib/ecdsa/_version.py
      error: [Errno 2] No such file or directory: 'build/lib/ecdsa/_version.py'
      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
error: legacy-install-failure

× Encountered error while trying to install package.
╰─> ecdsa

Adding ecdsa==0.14.1 in requirements.txt seems to have fixed the error above.

Not sure if you ran into this error, My setup (Docker version 20.10.3, docker-compose version 1.28.2, Ubuntu 20.04.2 LTS, GNU Make 4.2.1)