fix: update links to SECURITY.md

[vil02]

Description

The links to SECURITY.md in:

• https://github.com/openfga/java-sdk/blob/4947d98a11711eddfbde88caacf36af77da5dcbd/CONTRIBUTING.md?plain=1#L46,
• https://github.com/openfga/java-sdk/blob/4947d98a11711eddfbde88caacf36af77da5dcbd/.github/ISSUE_TEMPLATE/bug_report.md?plain=1#L10,

are broken.

Similarly in go-sdk, python-sdk, and dotned-sdk.

I decided to link directly to SECURITY.md.

References

Review Checklist

• I have clicked on "allow edits by maintainers".
• I have added documentation for new/changed functionality in this PR or in a PR to openfga.dev [Provide a link to any relevant PRs in the references section above]
• The correct base branch is being used, if not main
• I have added tests to validate that the change in functionality is working as expected

[ewanharris]

Thanks @vil02!