fix: make things compile with no default features

Testing with the `--no-default-features` did not work. This commit fixes it
and also improves the CI, so that it doesn't happen again.

.github/workflows/build.yml

@@ -30,16 +30,24 @@ jobs:
 
       - name: Check Code Format
         run: cargo fmt --all -- --check
-        shell: bash
 
-      - name: Code Lint
+      - name: Code lint with default features
         run: cargo clippy --all-targets --workspace -- -D warnings
-        shell: bash
 
-      - name: Test
+      - name: Code lint without default features
+        run: cargo clippy --all-targets --workspace --no-default-features -- -D warnings
+
+      - name: Code lint with all features
+        run: cargo clippy --all-targets --workspace --all-features -- -D warnings
+
+      - name: Test with default features
         run: cargo test --all-targets --workspace
-        shell: bash
+
+      - name: Test without default features
+        run: cargo test --all-targets --workspace --no-default-features
+
+      - name: Test with all features
+        run: cargo test --all-targets --workspace --all-features
 
       - name: Test no-cid-as-bytes feature
         run: cargo test --all-targets --workspace --features no-cid-as-bytes
-        shell: bash

src/ser.rs

@@ -1,8 +1,6 @@
 //! Serialization.
 #[cfg(not(feature = "std"))]
-use alloc::collections::TryReserveError;
-#[cfg(not(feature = "std"))]
-use alloc::vec::Vec;
+use alloc::{collections::TryReserveError, string::ToString, vec::Vec};
 #[cfg(feature = "std")]
 use std::collections::TryReserveError;