Update centrally managed files (#42)

* update SECURITY.md

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Co-authored-by: soleng-terraform[bot] <168111096+soleng-terraform[bot]@users.noreply.github.com>

SECURITY.md

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+<!-- This file is centrally managed as a template file in https://github.com/canonical/solutions-engineering-automation -->
+<!-- To update the file: -->
+<!-- - Edit it in the canonical/solutions-engineering-automation repository. -->
+<!-- - Open a PR with the changes. -->
+<!-- - When the PR merges, the soleng-terraform bot will open a PR to the target repositories with the changes. -->
+
+# Security policy
+
+
+## Reporting a vulnerability
+To report a security issue, file a [Private Security Report](https://github.com/canonical/charm-nginx/security/advisories/new)
+with a description of the issue, the steps you took to create the issue, affected versions, and,
+if known, mitigations for the issue.
+
+The [Ubuntu Security disclosure and embargo policy](https://ubuntu.com/security/disclosure-policy)
+contains more information about what you can expect when you contact us and what we expect from you.