SIANXSVC-1203: Ensure library_version has correct value

We now use the assembly name, which seems to be the way forward. A test
was also added to check whether the fallback value (1.0.0.0) is
returned.

Closes SIANXSVC-1203

src/Anexia.E5E.Tests/Serialization/SerializationTests.cs

@@ -136,7 +136,8 @@ public void MetadataIsProperSerialized()
 			() => Assert.Contains("runtime", sut),
 			() => Assert.Contains("features", sut),
 			() => Assert.Contains("library_version", sut),
-			() => Assert.Equal(1, sut["features"].GetArrayLength())
+			() => Assert.Equal(1, sut["features"].GetArrayLength()),
+			() => Assert.Equal("1.0.0.0", sut["library_version"].GetString())
 		);
 	}
 

src/Anexia.E5E/Runtime/E5ERuntimeMetadata.cs

@@ -1,5 +1,4 @@
 using System.Diagnostics.CodeAnalysis;
-using System.Reflection;
 
 namespace Anexia.E5E.Runtime;
 
@@ -18,9 +17,9 @@ public record E5ERuntimeMetadata
 	/// <summary>
 	///     The installed version of this NuGet library.
 	/// </summary>
-	public string LibraryVersion =>
-		typeof(E5ERuntimeMetadata).Assembly.GetCustomAttribute<AssemblyVersionAttribute>()?.Version ??
-		"0.0.0-unrecognized";
+	// CC-BY-SA 4.0 lastlink: https://stackoverflow.com/a/57157323
+	public string LibraryVersion => typeof(E5ERuntimeMetadata).Assembly.GetName().Version?.ToString()
+	                                ?? "0.0.0-unrecognized";
 
 	/// <summary>
 	///     The runtime this function is running in.