Bump validators from 0.12.2 to 0.12.6

Bumps [validators](https://github.com/kvesteri/validators) from 0.12.2 to 0.12.6.
- [Release notes](https://github.com/kvesteri/validators/releases)
- [Changelog](https://github.com/kvesteri/validators/blob/master/CHANGES.rst)
- [Commits](https://github.com/kvesteri/validators/commits)

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

requirements.txt

@@ -3,7 +3,7 @@ jingtrang==0.1.1
 requests>=2.8.1
 prettytable==0.7.2
 ansicolors==1.0.2
-validators==0.12.2
+validators==0.12.6
 # test requirements
 six>=1.10.0
 mock==1.3.0