ci: show sccache version and prefix (#31317)

* ci: Show sccache version as well

* hmm, where's sccache?? (and prefix bonus)

* Use $PATH's sccache for consistency

ci/docker-run.sh

@@ -54,7 +54,7 @@ if [[ -n $CI ]]; then
       # sccache-related bugs
       echo "--- $0 ... (with sccache being DISABLED due to many (${BUILDKITE_RETRY_COUNT}) retries)"
     else
-      echo "--- $0 ... (with sccache enabled)"
+      echo "--- $0 ... (with sccache enabled with prefix: $SCCACHE_S3_KEY_PREFIX)"
       # sccache
       ARGS+=(
         --env "RUSTC_WRAPPER=/usr/local/cargo/bin/sccache"

ci/test-checks.sh

@@ -46,6 +46,8 @@ echo --- build environment
   cargo audit --version
 
   grcov --version
+
+  sccache --version
 )
 
 export RUST_BACKTRACE=1