Upgrade Python dependencies

[pantierra]

Upgrading some Python dependencies.

Superseeding:

• Bump alembic from 1.3.2 to 1.3.3 #2243 (alembic to 1.3.3)
• Bump jinja2 from 2.10.3 to 2.11.1 #2269 (jinja2 to 2.11.1)
• Bump mako from 1.1.0 to 1.1.1 #2227 (mako to 1.1.1)
• Bump python-dotenv from 0.10.3 to 0.10.5 #2221 (python-dotenv to 0.10.5)
• Bump pyproj from 2.2.1 to 2.4.2.post1 #2217 (pyproj to 2.4.2.post1)
• Bump pyparsing from 2.4.2 to 2.4.6 #2214 (pyparsing to 2.4.6)
• Bump gunicorn from 19.9.0 to 20.0.4 #2213 (gunicorn to 20.0.4)
• Bump transifex-client from 0.13.4 to 0.13.7 #2212 (transifex-client to be removed)
• Bump werkzeug from 0.15.5 to 0.16.0 #2211 (wekzeug to 0.16.1)
• Bump pyyaml from 5.2 to 5.3 #2210 (pyyaml to 5.3 )
• Bump urllib3 from 1.25.7 to 1.25.8 #2236 (urllib3 to 1.25.8
• Bump shapely from 1.6.4.post2 to 1.7.0 #2261 (shapely to 1.7.0)
• Bump mako from 1.1.0 to 1.1.1 #2227 (mako to 1.1.1.)