fix: Fix README.md: enableSourceCodeIntegration is wrong

[exoego]

What does this PR do?

Change enableSourceCodeIntegration to sourceCodeIntegration in README

Motivation

TypeScript compiler claims that there is no enableSourceCodeIntegration property.

datadog-cdk-constructs/v2/src/interfaces.ts

Line 38 in 3d1f12b

readonly sourceCodeIntegration?: boolean;

Testing Guidelines

N/A

Additional Notes

N/A

Types of Changes

• Bug fix
• New feature
• Breaking change
• Misc (docs, refactoring, dependency upgrade, etc.)

Check all that apply

• This PR's description is comprehensive
• This PR contains breaking changes that are documented in the description
• This PR introduces new APIs or parameters that are documented and unlikely to change in the foreseeable future
• This PR impacts documentation, and it has been updated (or a ticket has been logged)
• This PR's changes are covered by the automated tests
• This PR collects user input/sensitive content into Datadog

[jhgilbert]

No review needed from Documentation on this change.

[duncanista]

Thanks for your contribution! 🙇🏽