Update workflow

[jochemvogel]

In the workflows (Github Actions) we use environment variables/secrets. Those are not accessible in forked repos. So when people try to make a change, the CI will fail, because they don't have access to the secrets.

Update pull_request to pull_request_target will probably do the trick. This isn't a very safe way according this article, but for this repo that's not a big deal.

Github fixed it tho, but (logically) only for private repos.

Only necessary for the Development CI, that's the only one that's triggered when a fork is being merged.

https://github.com/jochemvogel/ictmethods.nl/pull/47

Sources:

• https://docs.github.com/en/actions/security-guides/encrypted-secrets
• https://github.blog/2020-08-03-github-actions-improvements-for-fork-and-pull-request-workflows/