Bump whitenoise from 4.1.3 to 4.1.4

Bumps [whitenoise](https://github.com/evansd/whitenoise) from 4.1.3 to 4.1.4.
- [Release notes](https://github.com/evansd/whitenoise/releases)
- [Changelog](https://github.com/evansd/whitenoise/blob/master/docs/changelog.rst)
- [Commits](evansd/whitenoise@v4.1.3...v4.1.4)

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

requirements.txt

@@ -42,4 +42,4 @@ slacker==0.13.0
 twython==3.7.0
 untangle==1.1.1
 # Werkzeug==0.14.1
-whitenoise==4.1.3
+whitenoise==4.1.4