Make JDK21 available as toolchain in main build

See gh-30339
See gh-30241

ci/scripts/build-project.sh

@@ -5,5 +5,6 @@ source $(dirname $0)/common.sh
 repository=$(pwd)/distribution-repository
 
 pushd git-repo > /dev/null
-./gradlew -Dorg.gradle.internal.launcher.welcomeMessageEnabled=false --no-daemon --max-workers=4 -PdeploymentRepository=${repository} build publishAllPublicationsToDeploymentRepository
+./gradlew -Dorg.gradle.internal.launcher.welcomeMessageEnabled=false -Porg.gradle.java.installations.fromEnv=JDK17,JDK21 \
+  --no-daemon --max-workers=4 -PdeploymentRepository=${repository} build publishAllPublicationsToDeploymentRepository
 popd > /dev/null