Update base image to Elixir 1.14

What does this MR do?

Update base image to Elixir 1.14. Followup to !104 (merged). See context linked from gitlab-org/gitlab#424530.

Recommendation: Provide the MR image to customer for testing and merge if results are favorable.

What are the relevant issue numbers?

Update base image of Sobelow-based SAST analyze... (gitlab-org/gitlab#424530)

Does this MR meet the acceptance criteria?

• Changelog entry added
• Documentation created/updated for GitLab EE, if necessary
• Documentation created/updated for this project, if necessary
• Documentation reviewed by technical writer or follow-up review issue created
• Tests updated/added for this feature/bug
• Job definition updated, if necessary
  • Auto-DevOps template
  • Job definition example
  • CI Templates
• Conforms to the code review guidelines
• Conforms to the Go guidelines
• Security reports checked/validated by reviewer