refactor: object screen types

lib/graphql/github_object.graphql

@@ -0,0 +1,16 @@
+query($owner: String!, $name: String!, $expression: String!) {
+  repository(owner: $owner, name: $name) {
+    object(expression: $expression) {
+      __typename
+      ... on Tree {
+        entries {
+          type
+          name
+        }
+      }
+      ... on Blob {
+        text
+      }
+    }
+  }
+}