Upgrade to hibernate-jenkins-pipeline-helpers 1.18 -- and configure the version on CI instead of in Jenkinsfile

[yrodiere]

Upgrade to 1.18 to avoid buggy notifications.
See https://hibernate.zulipchat.com/#narrow/channel/132096-hibernate-user/topic/Jenkins.20Notifications
Full changeset: https://github.com/hibernate/hibernate-jenkins-pipeline-helpers/compare/1.17..1.18

Don't configure the version in Jenkinsfile so that it's easier to upgrade next time.
See https://ci.hibernate.org/manage/configure#global-untrusted-pipeline-libraries to change the (default) version globally for all projects.

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[marko-bekhta]

This looks nice 🎉 🥳 less version updates to think about 😄

Thinking of whether this can be a problem in the future, I could only come up with this case:
If we introduce a breaking change in the helper lib, then we'd need to go back to all (maintained) branches (where the version is not specified) to adjust the Jenkins file (since it doesn't point to a particular version anymore)

[yrodiere]

Thinking of whether this can be a problem in the future, I could only come up with this case: If we introduce a breaking change in the helper lib, then we'd need to go back to all (maintained) branches (where the version is not specified) to adjust the Jenkins file (since it doesn't point to a particular version anymore)

Yep. So let's not do that :)

[marko-bekhta]

let's keep that in mind 😄
Thanks!