Make default: --cli-connect-timeout 6000

**Is your feature request related to a problem? Please describe.**
Problem: timeouts when using `aws lambda update-function-code` to upload zip file.
See the many problem reports: https://github.com/aws/aws-cli/issues/3842 and [StackOverflow](https://superuser.com/q/1604904/23334)

**Describe the solution you'd like**
Please make the option `--cli-connect-timeout 6000` be a default option

**Describe alternatives you've considered**
Require devs with this problem to search for the answer. (Current situation.)

**Additional context**
Making this change will not slow anything down, it simply solves the not uncommon case of slow networking and proxies.