Mailer Plugin (mailer) has breaking changes in newest version

This is a clone of issue OCPBUGS-11489. The following is the description of the original issue:
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This is a clone of issue OCPBUGS-11348. The following is the description of the original issue:
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This is a clone of issue OCPBUGS-11329. The following is the description of the original issue:
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This is a clone of issue OCPBUGS-11158. The following is the description of the original issue:
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The Mailer Plugin (mailer) version 435.438.v5b_81173f5b_a_1 is not compatible with the Pipeline: Basic Steps (workflow-basic-steps) plugin version 2.20.

Both plugins need to be updated to newer versions at the same time per https://github.com/jenkinsci/mailer-plugin/releases/tag/435.v79ef3972b_5c7