Incorrect download links for Zig 0.14.0 in index.json

In index.json, the download links for Zig 0.14.0 are currently set under https://ziglang.org/builds/, whereas until Zig 0.13.0, they were placed under https://ziglang.org/download/.
This issue proposes modifying the links to be consistent with the previous versions by placing them in the expected location.