build: bump version to 0.4.0

 build.zig.zon | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/build.zig.zon b/build.zig.zon
index 12bff77..1d66851 100644
--- a/build.zig.zon
+++ b/build.zig.zon
@@ -8,7 +8,7 @@
     // commit that gets tagged.
     // Directly after the tagged commit, the version should be bumped and the
     // "-dev" suffix added.
-    .version = "0.4.0-dev",
+    .version = "0.4.0",
     .paths = .{""},
     .dependencies = .{
         .pixman = .{