Fixing the dependency error. Certifi's last python 2.7 release is 2020.04.5, otherwise the docker run command will raise a error.

Update Dockerfile

Bumps [requests](https://github.com/psf/requests) from 2.20.0 to 2.32.4.
- [Release notes](https://github.com/psf/requests/releases)
- [Changelog](https://github.com/psf/requests/blob/main/HISTORY.md)
- [Commits](psf/requests@v2.20.0...v2.32.4)

---
updated-dependencies:
- dependency-name: requests
  dependency-version: 2.32.4
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

….32.4

Bump requests from 2.20.0 to 2.32.4

Python 2.7 was very sad with dependabot's change.  Fixed!

Also three docker improvements:

- Make development easier with docker by using the
  files from the current directory instead of checking out
  a fresh copy.  This clutters the top level directory a bit,
  but it feels like a good tradeoff.

- Have the docker app listen on port 8080 by default, as fiddling with port 80 is a bit scary

- Have the docker app accept commandline parameters

And, finally, a README.md improvement:

- Show an example script to tickle three vulnerabilities in vuln_apps

Fix overeager requests update incompatible with python 2.7