fix(docs): repoint references to the relocated contributing guide

The guide moved to .github/CONTRIBUTING.md; these references still resolved
against the old root location and 404 from where they are written. Rewritten
using the correct relative depth.

- `QUICKSTART-DEV.adoc`: CONTRIBUTING.md -> .github/CONTRIBUTING.md
- `SECURITY.adoc`: CONTRIBUTING.md -> .github/CONTRIBUTING.md
- `docs/QUICKSTART.adoc`: ../CONTRIBUTING.md -> ../.github/CONTRIBUTING.md

Author: hyperpolymath

QUICKSTART-DEV.adoc

@@ -36,4 +36,4 @@ just assail    # run panic-attacker security scan
 
 == Contributing
 
-See link:CONTRIBUTING.md[CONTRIBUTING.md] for guidelines.
+See link:.github/CONTRIBUTING.md[CONTRIBUTING.md] for guidelines.

SECURITY.adoc

@@ -410,7 +410,7 @@ When using cloudguard-cli, we recommend:
 * https://github.com/hyperpolymath/cloudguard-cli/security/advisories[Security
 Advisories]
 * link:CHANGELOG.md[Changelog]
-* link:CONTRIBUTING.md[Contributing Guidelines]
+* link:.github/CONTRIBUTING.md[Contributing Guidelines]
 * https://cve.mitre.org/[CVE Database]
 * https://www.first.org/cvss/calculator/3.1[CVSS Calculator]
 

docs/QUICKSTART.adoc

@@ -56,7 +56,7 @@ docs/        # Documentation
 
 * Browse the link:.[docs/] for architecture and conventions
 * Run `+just --list+` to see all available commands
-* Read link:../CONTRIBUTING.md[CONTRIBUTING.md] when you are ready to
+* Read link:../.github/CONTRIBUTING.md[CONTRIBUTING.md] when you are ready to
 contribute
 
 === Troubleshooting