Update CI config (#101)

* Update actions/checkout action to v4

* Replace unmaintained actions-rs/toolchain action

* Cache cargo-expand

* Remove outdated ignore list from dependabot config

.github/dependabot.yml

@@ -6,13 +6,6 @@ updates:
     interval: daily
     time: "21:00"
   open-pull-requests-limit: 10
-  ignore:
-  - dependency-name: rand
-    versions:
-    - "> 0.7.3, < 1"
-  - dependency-name: rand
-    versions:
-    - ">= 0.8.a, < 0.9"
 - package-ecosystem: cargo
   directory: "/test-procmacro-project"
   schedule:

.github/workflows/ci.yml

@@ -16,20 +16,19 @@ jobs:
         os: [ubuntu, macos, windows]
 
     steps:
-      - uses: actions/checkout@v3
-
-      - uses: actions-rs/toolchain@v1
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: ${{matrix.rust}}
-          profile: minimal
-          override: true
+          toolchain: ${{ matrix.rust }}
 
       # A nightly toolchain is required for cargo-expand to work, even if the
       # toolchain with which tests are run is not nightly.
       - run: rustup toolchain install nightly
         if: matrix.rust != 'nightly'
 
-      - run: cargo install cargo-expand
+      - uses: taiki-e/cache-cargo-install-action@v1
+        with:
+          tool: cargo-expand
 
       - run: cargo test --manifest-path test-project/Cargo.toml -- --nocapture