Specific version of indexmap (#75)

I chose a specific version of indexmap (1.6.2) because of problems with cyclic dependency (1.7.0). Version 1.6.2 used in current diem release.

Author: RIg410

Cargo.lock

@@ -35,6 +35,7 @@ git2 = "0.13"
 bcs = "0.1.2"
 dunce = "1.0.1"
 atty = "0.2"
+indexmap = { version = "=1.6.2", default-features = false, features = ["std"] }
 
 lang = { path = "../lang" }
 decompiler = { path = "../lang/decompiler" }