Revert "build:rust: temporarily pin the rust version"
Revert "build:rust: temporarily pin the rust version"

This reverts commit 92d757e9cc12322e6318cd5244395ce298ca0cee.

Reason for revert: rust_toolchain_latest is in sync with 2022-06-28

Change-Id: I7c3501e1af37d053a70c663d7c6fc7b53175f740
GitOrigin-RevId: 040429b0eccbdde9cace932a835ece7374aef3e1

AmbiML/sparrow-build