fix: Bump unity package version with release

Author: AngelOnFira

.release_please_manifest.json

@@ -0,0 +1,10 @@
+{
+    ".": "1.0.2",
+    "extra-files": [
+        {
+            "type": "json",
+            "path": "Assets/Rivet/package.json",
+            "jsonpath": "$.version"
+        }
+    ]
+}