Switch soon to become default checkout method on CircleCI

It is not used by default yet, so switch to it explicitly as using it
results in much faster checkout times.

See https://circleci.com/changelog/introducing-a-faster-checkout-option/

Closes #25872.

.circleci/config.yml

@@ -10,7 +10,8 @@ jobs:
           name: Install Git
           command: dnf install -y git
 
-      - checkout
+      - checkout:
+          method: blobless
 
       - run:
           name: Install dependencies