Bump showdown and @patternfly/quickstarts

Bumps [showdown](https://github.com/showdownjs/showdown) to 2.1.0 and updates ancestor dependency [@patternfly/quickstarts](https://github.com/patternfly/patternfly-quickstarts). These dependencies need to be updated together.


Updates `showdown` from 1.8.6 to 2.1.0
- [Release notes](https://github.com/showdownjs/showdown/releases)
- [Changelog](https://github.com/showdownjs/showdown/blob/master/CHANGELOG.md)
- [Commits](showdownjs/showdown@1.8.6...2.1.0)

Updates `@patternfly/quickstarts` from 5.0.0 to 5.1.0
- [Release notes](https://github.com/patternfly/patternfly-quickstarts/releases)
- [Commits](patternfly/patternfly-quickstarts@v5.0.0...v5.1.0)

---
updated-dependencies:
- dependency-name: showdown
  dependency-type: indirect
- dependency-name: "@patternfly/quickstarts"
  dependency-type: direct:production
...

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