Use built-in fromisoformat instead of python-dateutil

[daveisfera]

Describe the feature

Currently, python-dateutil is used to parse dates, but fromisoformat is now a built-in option that should be used instead. It was significantly improved in 3.11 to allow this use and it's available through a back port package for older versions:
backports-datetime-fromisoformat; python_version < '3.11')

Use Case

Currently, have to install an extra dependency that has caused problems in the past so this removes the dependency to minimize and simplify botocore

Proposed Solution

Replace uses of python-dateutil with built-in parsing

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

SDK version used

1.32.5

Environment details (OS name and version, etc.)

N/A

[tim-finnigan]

Hi @daveisfera, thank you for the feature request. The team is looking into solutions to mitigate warnings on 3.12 (see: boto/boto3#3889) and datetime parsing performance.