Install dev-dependencies before running tests.

Author: brocaar

.github/workflows/main.yml

@@ -30,6 +30,9 @@ jobs:
             ~/.cargo/git/db/
             target/
           key: ${{ runner.os }}-cargo-test-${{ hashFiles('**/Cargo.lock') }}
+      -
+        name: Install dev dependencies
+        run: nix-shell --command "make dev-dependencies"
       -
         name: Run tests
         run: nix-shell --command "make test"