Speed up CI (#20)

CI was indeed sped up

.github/workflows/test.yml

@@ -1,41 +1,55 @@
 name: Cargo Build & Test
 
 on:
-  push:
   pull_request:
 
 env:
   CARGO_TERM_COLOR: always
 
 jobs:
-  build_and_test:
-    name: Rust project - latest
+  build:
+    name: Build Rust project - latest
     runs-on: ubuntu-latest
     strategy:
       matrix:
         toolchain:
           - stable
-          - beta
+          # - beta
+          # - nightly
+        crate:
+          # - instruct-macros
+          - instructor
+    steps:
+      - uses: actions/checkout@v4
+      - name: Cache Rust dependencies
+        uses: Swatinem/rust-cache@v2
+        with:
+          path: ${{ matrix.crate }}
+      - run: rustup update ${{ matrix.toolchain }} && rustup default ${{ matrix.toolchain }}
+      - run: cd ${{ matrix.crate }} && cargo build --verbose
+
+  test:
+    name: Test Rust project - latest
+    runs-on: ubuntu-latest
+    needs: build
+    strategy:
+      matrix:
+        toolchain:
+          # - stable
+          # - beta
           - nightly
         crate:
-          - instruct-macros
+          # - instruct-macros
           - instructor
     steps:
       - uses: actions/checkout@v4
-      - name: Cache cargo-nextest
-        id: cargo-nextest-cache
-        uses: actions/cache@v3
+      - name: Cache Rust dependencies
+        uses: Swatinem/rust-cache@v2
         with:
-          path: ~/.cargo/bin/cargo-nextest
-          key: ${{ runner.os }}-cargo-nextest-${{ matrix.toolchain }}-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-cargo-nextest-${{ matrix.toolchain }}-
-            ${{ runner.os }}-cargo-nextest-
+          path: ${{ matrix.crate }}
       - name: Install cargo-nextest
-        if: steps.cargo-nextest-cache.outputs.cache-hit != 'true'
         run: cargo install cargo-nextest --locked
       - run: rustup update ${{ matrix.toolchain }} && rustup default ${{ matrix.toolchain }}
-      - run: cd ${{ matrix.crate }} && cargo build --verbose
       - run: cd ${{ matrix.crate }} && cargo nextest run --verbose --retries 3
     env:
       OPENAI_API_KEY: ${{ secrets.OPENAI_API_KEY }}