Bump urllib3 from 1.22 to 1.24.2 in /intro-dnac

Bumps [urllib3](https://github.com/urllib3/urllib3) from 1.22 to 1.24.2.
- [Release notes](https://github.com/urllib3/urllib3/releases)
- [Changelog](https://github.com/urllib3/urllib3/blob/master/CHANGES.rst)
- [Commits](urllib3/urllib3@1.22...1.24.2)

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

Author: dependabot[bot]

intro-dnac/requirements.txt

@@ -1,3 +1,3 @@
 ciscosparkapi==0.9.2
 requests==2.18.4
-urllib3==1.22
+urllib3==1.24.2