Remove unnecessary typenum dependency from CI

Author: ConstanceBeguier

.github/workflows/ci.yml

@@ -65,10 +65,6 @@ jobs:
       - name: Add lazy_static with the spin_no_std feature
         working-directory: ./ci-build
         run: cargo add lazy_static --no-default-features --features "spin_no_std"
-      - name: Add typenum
-        working-directory: ./ci-build
-        # typenum is already no_std; no feature needed
-        run: cargo add typenum --no-default-features
       - name: Show Cargo.toml for the synthetic crate
         working-directory: ./ci-build
         run: cat Cargo.toml