ci: Check the formatting of build.zig.zon

 .builds/alpine.yml    | 1 +
 .builds/archlinux.yml | 1 +
 2 files changed, 2 insertions(+)

diff --git a/.builds/alpine.yml b/.builds/alpine.yml
index e365c0f..5e0a554 100644
--- a/.builds/alpine.yml
+++ b/.builds/alpine.yml
@@ -57,3 +57,4 @@ tasks:
       zig fmt --check riverctl/
       zig fmt --check rivertile/
       zig fmt --check build.zig
+      zig fmt --check build.zig.zon
diff --git a/.builds/archlinux.yml b/.builds/archlinux.yml
index 476e0ac..d37fb66 100644
--- a/.builds/archlinux.yml
+++ b/.builds/archlinux.yml
@@ -55,3 +55,4 @@ tasks:
       zig fmt --check riverctl/
       zig fmt --check rivertile/
       zig fmt --check build.zig
+      zig fmt --check build.zig.zon