Update @iobroker/adapter-core requirement from ^2.5.1 to ^2.6.0

Updates the requirements on [@iobroker/adapter-core](https://github.com/ioBroker/adapter-core) to permit the latest version.
- [Release notes](https://github.com/ioBroker/adapter-core/releases)
- [Commits](https://github.com/ioBroker/adapter-core/compare/v2.5.1...v2.6.0)

---
updated-dependencies:
- dependency-name: "@iobroker/adapter-core"
  dependency-type: direct:production
...

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

package.json

@@ -27,7 +27,7 @@
   "dependencies": {
     "websocket": "^1.0.34",
     "ws": "^8.2.3",
-    "@iobroker/adapter-core": "^2.5.1"
+    "@iobroker/adapter-core": "^2.6.0"
   },
   "devDependencies": {
     "@alcalzone/release-script": "^2.2.1",