Add artifact upload step to CI workflow

This commit adds a step to upload build artifacts using GitHub Actions. The artifacts, specifically plugin ZIP files, will be uploaded from the specified directory. This enhances the CI process by automatically archiving build outputs.

.github/workflows/main.yml

@@ -32,11 +32,18 @@ jobs:
       # Build the solution
       - name: Build solution
         run: msbuild "source\Plugins.Filter.slnf" /p:Configuration=Release /p:SkipSharedProject=true
-      
+
       - name: Create archives
         shell: pwsh
         run: source\zip-plugin-files.ps1
-          # Run tests (optional)
-          #- name: Run tests
-          #run: |
+
+      - name: Upload Artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: Plugins
+          path: C:\plugins\*.zip
+
+        # Run tests (optional)
+        #- name: Run tests
+        #run: |
         #vstest.console.exe path\to\your\test\project.dll