Build fails on Zig 0.15.0-dev.1228

``` build.zig:36:33: error: no field named 'root_source_file' in struct 'Build.TestOptions' const tests = b.addTest(.{ .root_source_file = b.path("src/chameleon.zig") }); ^~~~~~~~~~~~~~~~ C:\Users\evany\scoop\apps\zig-dev\0.15.0-dev.1228\lib\std\Build.zig:778:25: note: struct declared here pub const TestOptions = struct { ^~~~~~ referenced by: runBuild__anon_32097: C:\Users\evany\scoop\apps\zig-dev\0.15.0-dev.1228\lib\std\Build.zig:2136:33 main: C:\Users\evany\scoop\apps\zig-dev\0.15.0-dev.1228\lib\compiler\build_runner.zig:352:29 4 reference(s) hidden; use '-freference-trace=6' to see all references ```