Bump boto3 from 1.6.16 to 1.7.4

Bumps [boto3](https://github.com/boto/boto3) from 1.6.16 to 1.7.4.
- [Release notes](https://github.com/boto/boto3/releases)
- [Changelog](https://github.com/boto/boto3/blob/develop/CHANGELOG.rst)
- [Commits](https://github.com/boto/boto3/compare/1.6.16...1.7.4)

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

requirements.txt

@@ -17,7 +17,7 @@ requests==2.18.4
 datadog==0.8.0
 networkx==1.11
 pathlib2==2.3.0
-boto3==1.6.16
+boto3==1.7.4
 
 # Needed for the mongo_* modules (playbooks/library/mongo_*)
 pymongo==3.2.2

requirements3.txt

 # Needed for SES limits check job
-boto3==1.6.16
+boto3==1.7.4
 awscli==1.15.4