Create PR validation workflow for streampipes-website

[bossenti]

Body

Currently, there is no PR validation workflow in place for the streampipes-website repository.
As a firs iteration, we could create a workflow that builds both the website and the documentation.
This would help us to evaluate PR more easily and is of great help for dependency updates especially.

Mentoring

As this ticket is marked as good first issue: @bossenti is happy to provide help for getting started, just tag him if you want to start working on this issue and need some help.

StreamPipes Committer

• I acknowledge that I am a maintainer/committer of the Apache StreamPipes project.

[likileads]

Hi @bossenti, I wish to work on this issue.
Can you please guide me where to get started.

[bossenti]

Hi @likileads,

glad to hear!
Sure, you can find the concerned repository here: https://github.com/apache/streampipes-website
The idea of this issue is to build a GitHub actions workflow that is run on every PR.
This workflow should build both the website and the documentation (can be done in parallel).
How you can build website & docs is described here: https://github.com/apache/streampipes-website/blob/dev/README.md#build--run-website
If you need any other information, I'm happy to help :)

[likileads]

Hi @bossenti thanks for helping me out.
Please review my PR apache/streampipes-website#40