Misc: Remove AWS Example Key From PHPDoc

[lrljoe]

Fixes

This remediates the false-positive secret detection triggering for this package.

This is done by removing the Example key from the PHPDoc for "Create the AwsInstance"

     * @param string $credentials A string that contains the AWS access credentials in the format `<AWS_ACCESS_KEY_ID>:<AWS_SECRET_ACCESS_KEY>`. For example, `AKIAIOSFODNN7EXAMPLE:wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY`

The reason for this, is that it's presence triggers alerts by default in environments that look for the presence of secrets in code, for example, Azure automatically triggers an alert:
"Defender for Cloud found a plaintext AWS access key stored in this resource. It is important to store access keys securely to avoid leakage or misuse."

Removing the example does not break anything, although it does admittedly increase the barriers to entry, and it then silences the alert from being triggered.

Checklist

• I acknowledge that all my contributions will be made under the project's license
• I have made a material change to the repo (functionality, testing, spelling, grammar)
• I have read the Contribution Guidelines and my PR follows them
• I have titled the PR appropriately
• I have updated my branch with the main branch
• I have added tests that prove my fix is effective or that my feature works
• I have added the necessary documentation about the functionality in the appropriate .md file
• I have added inline documentation to the code I modified