Failed to run jpackage jtreg tests to create artifacts

An error appears when trying to run jtreg tests with JDK >= JDK18:

Error: The testsuite at /.../jdk/test/jdk requires jtreg version 6.1 b1 or higher and this is jtreg version 6+1-18

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Current commit hash: 7cf68b1901c

Steps:
- run jtreg tests using jtreg-6+1.tar.gz with JDK18