Add a cargo workspace containing both crates (#321)

* Move Cargo.toml for exercises to exercises directory.

* Create a workspace with both exercises and i18n-helpers.

* Build in CI as well as testing.

* Binaries must have a main function.

* No need for workspaces configuration for caching anymore.

.github/workflows/build.yml

@@ -34,13 +34,12 @@ jobs:
       - name: Setup Rust cache
         uses: ./.github/workflows/setup-rust-cache
 
+      - name: Build Rust code
+        run: cargo build
+
       - name: Test Rust code
         run: cargo test
 
-      - name: Test i18n-helpers
-        run: cargo test
-        working-directory: i18n-helpers
-
   i18n-helpers:
     runs-on: ubuntu-latest
     steps:

.github/workflows/setup-rust-cache/action.yml

@@ -7,7 +7,3 @@ runs:
   steps:
     - name: Setup Rust cache
       uses: Swatinem/rust-cache@v2
-      with:
-        workspaces: |
-          . -> target
-          i18n-helpers -> target