Auto merge of rust-lang#9641 - Alexendoo:sparse-registry, r=flip1995

Enable cargo sparse registry in CI

https://blog.rust-lang.org/2022/06/22/sparse-registry-testing.html

The initial registry update takes around 1 minute currently, so this gives quite a nice speed boost to CI build times

r? `@flip1995`

changelog: none

Author: bors

.github/workflows/clippy.yml

@@ -25,6 +25,7 @@ env:
   CARGO_TARGET_DIR: '${{ github.workspace }}/target'
   NO_FMT_TEST: 1
   CARGO_INCREMENTAL: 0
+  CARGO_UNSTABLE_SPARSE_REGISTRY: true
 
 jobs:
   base:

.github/workflows/clippy_bors.yml

@@ -11,6 +11,7 @@ env:
   CARGO_TARGET_DIR: '${{ github.workspace }}/target'
   NO_FMT_TEST: 1
   CARGO_INCREMENTAL: 0
+  CARGO_UNSTABLE_SPARSE_REGISTRY: true
 
 defaults:
   run:

.github/workflows/clippy_dev.yml

@@ -15,6 +15,8 @@ on:
 
 env:
   RUST_BACKTRACE: 1
+  CARGO_INCREMENTAL: 0
+  CARGO_UNSTABLE_SPARSE_REGISTRY: true
 
 jobs:
   clippy_dev: