Bump xml2js, aws-sdk and @datadog/datadog-ci in /serverless-al2-example

Bumps [xml2js](https://github.com/Leonidas-from-XIV/node-xml2js), [aws-sdk](https://github.com/aws/aws-sdk-js) and [@datadog/datadog-ci](https://github.com/DataDog/datadog-ci). These dependencies needed to be updated together.

Updates `xml2js` from 0.4.19 to 0.5.0
- [Commits](Leonidas-from-XIV/node-xml2js@0.4.19...0.5.0)

Updates `aws-sdk` from 2.1352.0 to 2.1378.0
- [Release notes](https://github.com/aws/aws-sdk-js/releases)
- [Commits](aws/aws-sdk-js@v2.1352.0...v2.1378.0)

Updates `@datadog/datadog-ci` from 2.7.0 to 2.10.0
- [Release notes](https://github.com/DataDog/datadog-ci/releases)
- [Commits](DataDog/datadog-ci@v2.7.0...v2.10.0)

---
updated-dependencies:
- dependency-name: xml2js
  dependency-type: indirect
- dependency-name: aws-sdk
  dependency-type: indirect
- dependency-name: "@datadog/datadog-ci"
  dependency-type: indirect
...

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Author: dependabot[bot]