Use actions/upload-artifact@v4

Author: mattt

.github/workflows/ci.yml

@@ -101,7 +101,7 @@ jobs:
         run: swift test -v
 
       - name: Upload build artifacts
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: alpine-binaries-${{ matrix.swift-version }}
           path: .build/x86_64-swift-linux-musl/debug
@@ -119,7 +119,7 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Download compiled binaries
-        uses: actions/download-artifact@v3
+        uses: actions/download-artifact@v4
         with:
           name: alpine-binaries-${{ matrix.swift-version }}
           path: .build/debug