AWS S3Upload task add --sync or equivalent operation

**Describe the bug**

Task isn't overwriting files that already exist

**To reproduce**

Run S3 Upload task in yaml pipeline to a bucket with a target file that already exists.

**Expected behavior**

Existing files should be overwritten.

**Screenshots**

**Your Environment**

- On-prem or cloud based?: Cloud
- Azure DevOps version: Cloud
- AWS Toolkit for Azure DevOps version: Cloud

**Additional context**

Start by locating the S3Upload task entry point and reviewing how it handles files that already exist. Done means an S3 upload run from a YAML pipeline overwrites an existing target file, with coverage for the reported reproduction.

Written by the indexing model from the issue text.