chore: upgrade crate versions

* mithril-client from `0.12.5` to `0.12.6`

Author: Alenar

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "mithril-client"
-version = "0.12.5"
+version = "0.12.6"
 description = "Mithril client library"
 authors = { workspace = true }
 edition = { workspace = true }