build.zig.zon: bump to 0.3.0

Author: thislight

build.zig.zon

@@ -10,7 +10,7 @@
 
     // This is a [Semantic Version](https://semver.org/).
     // In a future version of Zig it will be used for package deduplication.
-    .version = "0.2.1",
+    .version = "0.3.0",
 
     // This field is optional.
     // This is currently advisory only; Zig does not yet do anything