Heroku can't deploy, wants Python version 3 only

[calo1]

Tried to deploy after recent dependabot updates.
It seems like Heroku is only working with applications that have python 3:
https://devcenter.heroku.com/articles/python-support

Here is the build log with the error:
`-----> Node.js app detected

-----> Creating runtime environment

   NPM_CONFIG_LOGLEVEL=error
   NODE_ENV=production
   NODE_MODULES_CACHE=true
   NODE_VERBOSE=false

-----> Installing binaries
engines.node (package.json): 10.4.1
engines.npm (package.json): 5.6.0

   Resolving node version 10.4.1...
   Downloading and installing node 10.4.1...
   Bootstrapping npm 5.6.0 (replacing 6.1.0)...
   npm 5.6.0 installed

-----> Restoring cache
Cached directories were not restored due to a change in version of node, npm, yarn or stack
Module installation may take longer for this build

-----> Installing dependencies
Installing node modules (package.json + package-lock)

   > [email protected] postinstall /tmp/build_38359ad8e1d0a79236d466a65849e681/node_modules/uglifyjs-webpack-plugin
   > node lib/post_install.js
   
   
   > [email protected] postinstall /tmp/build_38359ad8e1d0a79236d466a65849e681
   > npm run build
   
   
   > [email protected] build /tmp/build_38359ad8e1d0a79236d466a65849e681
   > browserify src/pages/map-page.js -v -t [ babelify ] -g [ envify --NODE-ENV production ] -g uglifyify | uglifyjs --compress --mangle > static/src/pages/map-page.js
   
   added 1521 packages in 48.239s

-----> Build
Running build

   > [email protected] build /tmp/build_38359ad8e1d0a79236d466a65849e681
   > browserify src/pages/map-page.js -v -t [ babelify ] -g [ envify --NODE-ENV production ] -g uglifyify | uglifyjs --compress --mangle > static/src/pages/map-page.js

-----> Caching build
- node_modules

-----> Pruning devDependencies
Skipping because npm 5.6.0 sometimes fails when running 'npm prune' due to a known issue
npm/npm#19356

   You can silence this warning by updating to at least npm 5.7.1 in your package.json
   https://devcenter.heroku.com/articles/nodejs-support#specifying-an-npm-version

-----> Build succeeded!
-----> Python app detected
! Requested runtime (python-2.7.10) is not available for this stack (heroku-18).
! Aborting. More info: https://devcenter.heroku.com/articles/python-support
! Push rejected, failed to compile Python app.
! Push failed`

[calo1]

@stlim0730 discovered that Heroku requires a number of updates:

ecently, Heroku has stopped supporting a few dependencies of Farmview. According to their policy change, Farmview requires upgrades in them since it has used old versions of the tools. Also, some of community-maintained tools are deprecated or going to be out of the lifecycle.

So, I'm trying to upgrade:

• Heroku's Cedar-14 stack to Heroku-18- Python 2.7 to Python 3.X
• Django 1.7 to Django 2.2 or 3.0
• Ubuntu Xenial to Bionic (only for development environment)

In doing so, I faced an issue in spinning up the local instance on Vagrant. "Populate local database" part in development/provision.sh doesn't work properly. Is it a known issue? Any help would be appreciated.