cargo: Halt overzealous upgrader
We're using a version of Cargo which doesn't support 2021 edition. The dependency Hashbrown 0.12 uses it, so we perform a minimal reshuffling to use 0.11.
We're using a version of Cargo which doesn't support 2021 edition. The dependency Hashbrown 0.12 uses it, so we perform a minimal reshuffling to use 0.11.