[3.x] Prepare for SnakeYAML 2.0

[tjquinno]

Environment Details

• Helidon Version: 3.x
• Helidon SE or Helidon MP
• JDK version:
• OS:
• Docker version (if applicable):

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Problem Description

SnakeYAML 2.0 (not yet released but coming) contains backward-incompatible changes we need to accommodate.

See also #5823 for an analysis of Helidon's usage of SnakeYAML.

Steps to reproduce

Try to build helidon-config-yaml, helidon-config-yaml-mp, or helidon-openapi.