ci: Build plugin asset

.github/workflows/release-please.yml

@@ -14,6 +14,24 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: google-github-actions/release-please-action@v4
+        id: release
         with:
           token: ${{ secrets.GITHUB_TOKEN }}
           release-type: simple
+
+      - uses: game-ci/unity-builder@v2
+        if: ${{ steps.release.outputs.release_created }}
+        env:
+          UNITY_SERIAL: ${{ secrets.UNITY_SERIAL }}
+          UNITY_EMAIL: ${{ secrets.UNITY_EMAIL }}
+          UNITY_PASSWORD: ${{ secrets.UNITY_PASSWORD }}
+        with:
+          unityVersion: 2022.3.19f1
+          buildMethod: ExportPackage.Export
+          customImage: "unityci/editor:ubuntu-2022.3.19f1-base-3"
+
+      - name: Upload Release Artifact
+        if: ${{ steps.release.outputs.release_created }}
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: gh release upload ${{ steps.release.outputs.tag_name }} Rivet.unitypackage

Assets/Rivet/Editor/ExportPlugin.cs

@@ -0,0 +1,18 @@
+using System.Linq;
+using UnityEditor;
+
+/// <summary>
+/// Represents a class that exports a package containing assets related to the Rivet plugin.
+/// </summary>
+public class ExportPackage
+{
+    /// <summary>
+    /// Exports the assets related to the Rivet plugin as a Unity package.
+    /// </summary>
+    public static void Export()
+    {
+        string[] projectContent = AssetDatabase.GetAllAssetPaths();
+        var assetsToExport = projectContent.Where(path => path.StartsWith("Assets/Rivet")).ToArray();
+        AssetDatabase.ExportPackage(assetsToExport, "Rivet.unitypackage", ExportPackageOptions.Recurse);
+    }
+}