CI: Update actions to Node 20.

Author: whitequark

.github/workflows/main.yaml

@@ -24,15 +24,15 @@ jobs:
         include:
         - python-version: '3.13-dev'
           allow-failure: true
-    continue-on-error: '${{ matrix.allow-failure }}'
+    continue-on-error: ${{ matrix.allow-failure }}
     name: 'test (${{ matrix.python-version }})'
     steps:
     - name: Check out source code
-      uses: actions/checkout@v3
+      uses: actions/checkout@v4
       with:
         fetch-depth: 0
     - name: Set up PDM
-      uses: pdm-project/setup-pdm@v3
+      uses: pdm-project/setup-pdm@v4
       with:
         python-version: ${{ matrix.python-version }}
     - name: Install dependencies
@@ -44,7 +44,7 @@ jobs:
         pip install codecov build
         pdm install --dev
     - name: Cache YoWASP build products
-      uses: actions/cache@v3
+      uses: actions/cache@v4
       with:
         path: ~/.cache/YoWASP
         key: YoWASP-${{ runner.os }}-${{ hashFiles('./.venv/**/*.wasm') }}
@@ -54,21 +54,21 @@ jobs:
       run: |
         pdm run test
     - name: Submit code coverage
-      run:
+      run: |
         codecov
 
   document:
     runs-on: ubuntu-latest
     steps:
       - name: Check out source code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - name: Fetch tags from upstream repository
         run: |
           git fetch --tags https://github.com/amaranth-lang/amaranth.git
       - name: Set up PDM
-        uses: pdm-project/setup-pdm@v3
+        uses: pdm-project/setup-pdm@v4
         with:
           python-version: '3.11'
       - name: Install dependencies
@@ -78,7 +78,7 @@ jobs:
         run: |
           pdm run document
       - name: Upload documentation archive
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: docs
           path: docs/_build
@@ -87,27 +87,27 @@ jobs:
     needs:
       - test
       - document
-    if: always() && !contains(needs.*.result, 'cancelled')
+    if: ${{ always() && !contains(needs.*.result, 'cancelled') }}
     runs-on: ubuntu-latest
     steps:
       - run: ${{ contains(needs.*.result, 'failure') && 'false' || 'true' }}
 
   publish-docs:
     needs: document
-    if: github.repository == 'amaranth-lang/amaranth'
+    if: ${{ github.repository == 'amaranth-lang/amaranth' }}
     runs-on: ubuntu-latest
     steps:
       - name: Check out source code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - name: Download documentation archive
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4
         with:
           name: docs
           path: docs/
       - name: Publish development documentation
-        if: github.event_name == 'push' && github.event.ref == 'refs/heads/main'
+        if: ${{ github.event_name == 'push' && github.event.ref == 'refs/heads/main' }}
         uses: JamesIves/github-pages-deploy-action@releases/v4
         with:
           repository-name: amaranth-lang/amaranth-lang.github.io
@@ -116,7 +116,7 @@ jobs:
           folder: docs/
           target-folder: docs/amaranth/latest/
       - name: Publish release documentation
-        if: github.event_name == 'push' && startsWith(github.event.ref, 'refs/tags/v')
+        if: ${{ github.event_name == 'push' && startsWith(github.event.ref, 'refs/tags/v') }}
         uses: JamesIves/github-pages-deploy-action@releases/v4
         with:
           repository-name: amaranth-lang/amaranth-lang.github.io
@@ -127,15 +127,15 @@ jobs:
 
   publish-docs-dev:
     needs: document
-    if: github.repository != 'amaranth-lang/amaranth'
+    if: ${{ github.repository != 'amaranth-lang/amaranth' }}
     runs-on: ubuntu-latest
     steps:
       - name: Check out source code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           fetch-depth: 0
       - name: Download documentation archive
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4
         with:
           name: docs
           path: pages/docs/${{ github.ref_name }}/