modify IActivity definition and add IStrictActivity

types/git.ts

@@ -1,13 +1,21 @@
 declare global {
-  interface IActivity<T = string> {
+  interface IActivity {
     id: string
-    content: T
-    op_type: string
+    content: null | string | IContent
+    op_type: 'commit_repo' | 'create_repo' | 'delete_branch' | 'delete_tag' | 'merge_pull_request'
     repo: {
       name: string
       html_url: string
+      owner: {
+        login: string
+      }
     }
     created: string
+    ref_name: string
+  }
+
+  interface IStrictActivity extends IActivity {
+    content: IContent | null
   }
 
   interface IContent {