Give artifacts unique names.

Rationale: v4 of upload-artifact action fails when an artifact with the same name already exists on the workflow run.

See also: actions/upload-artifact#480

.github/workflows/build.yml

@@ -39,7 +39,7 @@ jobs:
       shell: cmd
     - uses: actions/upload-artifact@v4
       with:
-        name: artifacts
+        name: artifacts-windows-${{ strategy.job-index }}
         path: .\artifacts\pkg\**\*
         if-no-files-found: error
   build-linux:
@@ -67,7 +67,7 @@ jobs:
       shell: bash
     - uses: actions/upload-artifact@v4
       with:
-        name: artifacts
+        name: artifacts-linux-${{ strategy.job-index }}
         path: ./artifacts/pkg/**/*
         if-no-files-found: error
   build-multiplatform:
@@ -85,7 +85,7 @@ jobs:
       shell: cmd
     - uses: actions/upload-artifact@v4
       with:
-        name: artifacts
+        name: artifacts-multiplatform
         path: .\artifacts\pkg\**\*
         if-no-files-found: error
   publish-artifacts-on-azure:
@@ -95,7 +95,8 @@ jobs:
     steps:
     - uses: actions/download-artifact@v4
       with:
-        name: artifacts
+        pattern: artifacts-*
+        merge-multiple: true
         path: ./artifacts
     - uses: actions/setup-dotnet@v3
       with:
@@ -113,7 +114,8 @@ jobs:
     steps:
     - uses: actions/download-artifact@v4
       with:
-        name: artifacts
+        pattern: artifacts-*
+        merge-multiple: true
         path: ./artifacts
     - uses: actions/setup-dotnet@v3
       with: