add AssemblyAppVersionAttribute

Pilz/AssemblyAppVersion.cs

@@ -0,0 +1,17 @@
+using System.Reflection;
+
+namespace Pilz;
+
+[AttributeUsage(AttributeTargets.Assembly)]
+public class AssemblyAppVersionAttribute(string version, int build, AppChannel channel) : Attribute
+{
+    public AppVersion Version { get; } = new(new Version(version), build, channel);
+
+    public AssemblyAppVersionAttribute(string version) : this(version, 1)
+    {
+    }
+
+    public AssemblyAppVersionAttribute(string version, int build) : this(version, build, AppChannel.Stable)
+    {
+    }
+}

Pilz/Extensions/AssemblyExtensions.cs

@@ -0,0 +1,11 @@
+using System.Reflection;
+
+namespace Pilz.Extensions;
+
+public static class AssemblyExtensions
+{
+    public static AppVersion GetAppVersion(this Assembly @this)
+    {
+        return @this.GetCustomAttribute<AssemblyAppVersionAttribute>()?.Version ?? new();
+    }
+}