[MAINTENANCE] Missing or outdated SECURITY.md file in ansys/api-eigen-example

Please add the SECURITY.md file to the repository. The file might either be missing or is an outdated version of the expected file.

See [here](https://github.com/ansys-internal/pyansys-maintenance-automation/blob/main/scripts/file_references) an up-to-date reference to a properly formatted file.

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This issue was created by a bot. If you have any questions, please ping the PyAnsys Core team for assistance. To ping the team write a comment in this issue with the following mention: `@ansys/pyansys-core`.

If you want this repository to be excluded from this automated maintenance process, please let us know by [filling in the opt-out request form](https://github.com/ansys-internal/pyansys-maintenance-automation/issues/new?labels=&projects=&template=opt-out.yml&title=Request+to+opt-out+from+automated+maintenance+for+ansys%2Fapi-eigen-example).