Bump @transmute/ed25519-signature-2018 in /vc-modules

Bumps [@transmute/ed25519-signature-2018](https://github.com/transmute-industries/verifiable-data/tree/HEAD/packages/ed25519-signature-2018) from 0.7.0-unstable.8 to 0.7.0-unstable.28.
- [Release notes](https://github.com/transmute-industries/verifiable-data/releases)
- [Commits](https://github.com/transmute-industries/verifiable-data/commits/v0.7.0-unstable.28/packages/ed25519-signature-2018)

---
updated-dependencies:
- dependency-name: "@transmute/ed25519-signature-2018"
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

vc-modules/package.json

@@ -4,7 +4,7 @@
     "@hashgraph/sdk": "2.1.0",
     "@transmute/credentials-context": "0.7.0-unstable.8",
     "@transmute/did-context": "0.7.0-unstable.8",
-    "@transmute/ed25519-signature-2018": "0.7.0-unstable.8",
+    "@transmute/ed25519-signature-2018": "0.7.0-unstable.28",
     "@transmute/security-context": "0.7.0-unstable.8",
     "@transmute/vc.js": "0.7.0-unstable.8",
     "did-sdk-js": "git+https://github.com/EnvisionBlockchain/did-sdk-js.git"