add //:buildifier to lint rule

.build.yml

@@ -15,8 +15,10 @@ tasks:
   - setup: |
       sudo apt-get purge gcc -y && sudo apt-get autoremove -y
   - lint: |
-      cd bazel-zig-cc;
+      cd bazel-zig-cc; .envrc
       shellcheck -x $(awk '/#!\/bin\/(ba)?sh/&&FNR==1{print FILENAME}' $(git ls-files))
+      bazel run //:buildifier
+      git diff --exit-code
   - test_list_toolchains: |
       cd bazel-zig-cc; . .envrc; echo "Available toolchains:"
       bazel query @zig_sdk//... | sed -En '/.*_toolchain$/ s/.*:(.*)_toolchain$/\1/p'