Deprecate deps/eigen3

data/modules/deps/eigen3.json

 {
   "general": {
-    "url": "https://gitlab.com/libeigen/eigen"
+    "url": "https://gitlab.com/libeigen/eigen",
+    "deprecated": {
+      "since": "2023-01-27",
+      "removal": "2023-02-17",
+      "superseded_by": {
+        "apt/eigen3": {}
+      },
+      "message": "Due to potential conflicts with the apt version of Eigen, it is now recommend to use only the apt package of Eigen."
+    }
   },
 
   "update": {