CI improvements (#5)

* Run CI only on push

* Simplify CI

.github/workflows/ci.yaml

@@ -1,36 +1,15 @@
 name: CI
 on:
   push:
-  pull_request:
 
 jobs:
-  test:
-    name: Tests
+  checks:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: actions-rust-lang/setup-rust-toolchain@v1
-      - name: Run tests
-        run: cargo test --all-features
-
-  formatting:
-    name: Rustfmt
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions-rust-lang/setup-rust-toolchain@v1
-        with:
-          components: rustfmt
-      - name: Run rustfmt
-        run: cargo fmt
-
-  linting:
-    name: Clippy
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions-rust-lang/setup-rust-toolchain@v1
+      - uses: dtolnay/rust-toolchain@nightly
         with:
-          components: clippy
-      - name: Run Clippy
-        run: cargo clippy --all-targets --all-features
+          components: clippy, rustfmt
+      - run: cargo test --all-features
+      - run: cargo fmt
+      - run: cargo clippy --all-targets --all-features