Add --workspace flag to cargo check too

Without this flag, it looks like not all workspace files
are checked. You can test this by adding for example an
unused import (`use std::clone;`) in
rust-vmm/vmm-reference#11,
file src/vmm/tests/integration_tests.rs. cargo check will
fail only if we pass `--workspace` flag too.
For clippy, this flag doesn't seem to have an obvious
effect, this should be further investigated in #21.

Signed-off-by: Laura Loghin <[email protected]>

Author: lauralt

.buildkite/pipeline.yml

@@ -136,7 +136,7 @@ steps:
 
   - label: "check-warnings-x86"
     commands:
-      - RUSTFLAGS="-D warnings" cargo check --all-targets --all-features
+      - RUSTFLAGS="-D warnings" cargo check --all-targets --all-features --workspace
     retry:
       automatic: false
     agents:
@@ -150,7 +150,7 @@ steps:
 
   - label: "check-warnings-arm"
     command:
-     - RUSTFLAGS="-D warnings" cargo check --all-targets --all-features
+     - RUSTFLAGS="-D warnings" cargo check --all-targets --all-features --workspace
     retry:
       automatic: false
     agents: