integrate with new zig module system (#10)

Author: nektro

build.zig

@@ -0,0 +1,8 @@
+const std = @import("std");
+
+pub fn build(b: *std.Build) void {
+    b.addModule(.{
+        .name = "diffz",
+        .source_file = .{ .path = "DiffMatchPatch.zig" },
+    });
+}