chore(Jenkinsfile) switch WAR download to https://get.jenkins.io

[dduportal]

Ref. jenkins-infra/helpdesk#2888

This change also uses long flags for curl and shows if an error happens during the download (easier to diagnose)

Checked locally that it keeps the same behavior:

➜ curl --silent --show-error --location https://get.jenkins.io/war-stable/2.164.1/jenkins.war --output jenkins.war
➜ echo "65543f5632ee54344f3351b34b305702df12393b3196a95c3771ddb3819b220b jenkins.war" | sha256sum --check
jenkins.war: OK
➜ date
Thu May  5 12:20:52 CEST 2022

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[timja]

@jenkinsci/plugin-compat-tester-developers could this be merged please?

[jglick]

Better still, use mvn dependency:get.

[jglick]

Removing incorrect label, though too late as it already triggered a pointless release: https://github.com/jenkinsci/plugin-compat-tester/releases/tag/1176.vf035412416dd

@imonteroperez https://github.com/jenkins-infra/interesting-category-action/blob/53539d558c3480617e0c9f9757d9fcd604080c1a/action.yaml#L10-L11 FYI