As of Mailer 435.v79ef3972b_5c7 and Email Extension 2.90, the package namespace has changed from javax.mail to jakarta.mail. This plugin is still using the older package namespace, which may result in linkage errors. To resolve these errors:

• Ensure the plugin depends on Jenkins 2.332.1 or higher.
• If this plugin depends on Mailer, ensure the Mailer dependency is 435.v79ef3972b_5c7 or higher.
• If this plugin depends on Email Extension, ensure the Email Extension dependency is 2.90 or higher.
• Change any imports of javax.mail.* to instead import jakarta.mail.*.

This PR is an example of how to begin resolving this issue.