add export github action ReleaseVersion script

Author: WeihanLi

build/export-gh-release-version.cs

@@ -0,0 +1,17 @@
+var currentDirectory = Directory.GetCurrentDirectory();
+Console.WriteLine($"currentDirectory: {currentDirectory}");
+
+var versionPropsFile = "./build/version.props";
+var doc = System.Xml.Linq.XDocument.Load(versionPropsFile);
+var propertyGroupNode = doc.Element("Project").Element("PropertyGroup");
+
+var version = $"{propertyGroupNode.Element("VersionMajor").Value}.{propertyGroupNode.Element("VersionMinor").Value}.{propertyGroupNode.Element("VersionPatch").Value}";
+Console.WriteLine($"Version: {version}");
+
+var envFile = Environment.GetEnvironmentVariable("GITHUB_ENV");
+Console.WriteLine($"EnvFilePath: {envFile}");
+
+if (string.IsNullOrEmpty(envFile)) return;
+
+File.WriteAllText(envFile, $"ReleaseVersion={version}");
+Console.WriteLine(File.ReadAllText(envFile));