build: niv advisory-db: update b2af5ad8 -> 9b6403d8

## Changelog for advisory-db:
Branch: main
Commits: [rustsec/advisory-db@b2af5ad8...9b6403d8](rustsec/advisory-db@b2af5ad...9b6403d)

* [`9b6403d8`](rustsec/advisory-db@9b6403d) Add patch version ([RustSec/advisory-db⁠#1794](http://r.duckduckgo.com/l/?uddg=https://github.com/RustSec/advisory-db/issues/1794))

nix/sources.json

@@ -6,10 +6,10 @@
         "homepage": "https://rustsec.org",
         "owner": "RustSec",
         "repo": "advisory-db",
-        "rev": "b2af5ad8564a69a69ca66da8619cb9137926f118",
-        "sha256": "1yqmni1myslqhz8jpzxv8zi12p0sb2k9hz7cmbpl8zs7vw7a1c6b",
+        "rev": "9b6403d856f71291aabb91511b53fa79c2758745",
+        "sha256": "1b839a6bja6x1660737yfv7b7qfldcjd36g2s3a1v74q3f6zv5nw",
         "type": "tarball",
-        "url": "https://github.com/RustSec/advisory-db/archive/b2af5ad8564a69a69ca66da8619cb9137926f118.tar.gz",
+        "url": "https://github.com/RustSec/advisory-db/archive/9b6403d856f71291aabb91511b53fa79c2758745.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "canister_sandbox-x86_64-darwin": {