Update GitHub actions and drop legacy .NET versions

.github/workflows/ci-build.yml

@@ -25,29 +25,27 @@ jobs:
       VSTEST_CONNECTION_TIMEOUT: 900
 
     steps:
-      - uses: actions/checkout@v2
-      - name: Setup .NET Core
-        uses: actions/setup-dotnet@v1
+      - uses: actions/checkout@v4
+      - name: Setup .NET
+        uses: actions/setup-dotnet@v4
         with:
           dotnet-version: |
-            3.1.x
-            5.0.x
             6.0.x
-            7.0.x
+            8.0.x
       - name: Install dependencies
         run: dotnet restore src/${{ env.PROJECT_NAME }}.sln
       - name: Build solution
         run: dotnet build src/${{ env.PROJECT_NAME }}.sln -c Release --no-restore
       - name: Test
         run: dotnet test src/${{ env.PROJECT_NAME }}.sln -c Release --no-build /p:CollectCoverage=true /p:CoverletOutputFormat=opencover /p:CoverletOutput=../coverage/
-      - uses: codecov/codecov-action@v2
+      - uses: codecov/codecov-action@v4
         if: github.ref == 'refs/heads/main'
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
           directory: src/coverage
           flags: unittests
       - name: Upload Artifact
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
           name: nupkg
           path: src/${{ env.PROJECT_NAME }}/bin/Release/*.nupkg