chore(deps): update core to latest version

- Update core package to version 1.3.1 with new git reference
- This update includes the latest changes from the core repository

Author: fulleni

pubspec.lock

@@ -185,8 +185,8 @@ packages:
     dependency: "direct main"
     description:
       path: "."
-      ref: "8a03af9af8ccf4920388ddce73062aca2fde1bc9"
-      resolved-ref: "8a03af9af8ccf4920388ddce73062aca2fde1bc9"
+      ref: "643aa3830261d04806569defd013639c92eaf5a3"
+      resolved-ref: "643aa3830261d04806569defd013639c92eaf5a3"
       url: "https://github.com/flutter-news-app-full-source-code/core.git"
     source: git
     version: "1.3.1"

pubspec.yaml

@@ -145,7 +145,7 @@ dependency_overrides:
   core:
     git:
       url: https://github.com/flutter-news-app-full-source-code/core.git
-      ref: 8a03af9af8ccf4920388ddce73062aca2fde1bc9
+      ref: 643aa3830261d04806569defd013639c92eaf5a3
   http_client:
     git:
       url: https://github.com/flutter-news-app-full-source-code/http-client.git