bump indexmap dependency

Author: QEDK

Cargo.toml

@@ -19,4 +19,4 @@ maintenance = { status = "actively-developed" }
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-indexmap = { version = "1.7", optional = true }
+indexmap = { version = "1.9.1", optional = true }