chore(pkg): adjust contributors

package.json

@@ -2,7 +2,11 @@
   "name": "@d-ptb/dcc-js",
   "version": "1.4.1",
   "license": "EUPL-1.2",
-  "author": "Jan Loewe <jan.loewe@ptb.de>",
+  "contributors": [
+    "Jan Loewe <jan.loewe@ptb.de>",
+    "Moritz Jordan <moritz.jordan@ptb.de>",
+    "Muhammed-Ali Demir <muhammed.demir@ptb.de>"
+  ],
   "main": "lib/index.js",
   "typings": "lib/index.d.ts",
   "scripts": {