fix(ci): Setup std / no_std jobs

.github/workflows/pr_validation.yml

@@ -11,16 +11,27 @@ env:
   CARGO_TERM_COLOR: always
 
 jobs:
-  build_test_lint:
+  build_test_lint_std:
     runs-on: ubuntu-latest
 
     steps:
       - uses: actions/checkout@v3
+      - uses: dtolnay/rust-toolchain@stable
       - name: Install cargo-all-features
         run: cargo install cargo-all-features
       - name: Build
-        run: cargo build-all-features --verbose
+        run: cargo build-all-features  --exclude test_no_std --workspace --verbose
       - name: Run tests
-        run: cargo test-all-features --verbose
+        run: cargo test-all-features --exclude test_no_std --workspace --verbose
       - name: Run clippy
         run: cargo clippy --verbose
+
+  build_test_lint_no_std:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v3
+      # the test_no_std crate requires the nightly toolchain
+      - uses: dtolnay/rust-toolchain@nightly
+      - name: Build test_no_std
+        run: cd crates/test_no_std && cargo +nightly build --verbose