Bump prompt-toolkit from 3.0.26 to 3.0.28

Bumps [prompt-toolkit](https://github.com/prompt-toolkit/python-prompt-toolkit) from 3.0.26 to 3.0.28.
- [Release notes](https://github.com/prompt-toolkit/python-prompt-toolkit/releases)
- [Changelog](https://github.com/prompt-toolkit/python-prompt-toolkit/blob/master/CHANGELOG)
- [Commits](prompt-toolkit/python-prompt-toolkit@3.0.26...3.0.28)

---
updated-dependencies:
- dependency-name: prompt-toolkit
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

setup.py

@@ -91,7 +91,7 @@ def get_version(version_file):
         "docopt >= 0.6.2",
         "gophish >= 0.2.5",
         "httpagentparser",
-        "prompt-toolkit == 3.0.26",
+        "prompt-toolkit == 3.0.28",
         "pytz >= 2019.1",
         "schema",
         "setuptools >= 24.2.0",