Upgrade to Insta master to get bugfix.

Map sorting in Insta was previously not recursive.
As of this PR, it is!
https://github.com/mitsuhiko/insta/pull/80

Since it hasn't made it into a release yet, but is
important for Rojo to have snapshot determinism,
we're moving temporarily to depend on Insta via Git.

rojo-test/serve-test-snapshots/serve_test__add_folder_all-2.snap

@@ -4,23 +4,23 @@ expression: "read_response.intern_and_redact(&mut redactions, root_id)"
 ---
 instances:
   id-2:
-    Id: id-2
-    Parent: ~
-    Name: add_folder
-    ClassName: Folder
-    Properties: {}
     Children:
       - id-3
-    Metadata:
-      ignoreUnknownInstances: false
-  id-3:
-    Id: id-3
-    Parent: id-2
-    Name: my-new-folder
     ClassName: Folder
-    Properties: {}
-    Children: []
+    Id: id-2
     Metadata:
       ignoreUnknownInstances: false
+    Name: add_folder
+    Parent: ~
+    Properties: {}
+  id-3:
+    Children: []
+    ClassName: Folder
+    Id: id-3
+    Metadata:
+      ignoreUnknownInstances: false
+    Name: my-new-folder
+    Parent: id-2
+    Properties: {}
 messageCursor: 1
 sessionId: id-1