Can't add headers to sourcemap files

[Ian Storm Taylor]

Using the headers option works fine for file.js but for file.js.map the headers never get applied...

      await serveHandler(req, res, {
        public: outdir,
        headers: [
          {
            source: 'file.js',
            headers: [
              {
                key: 'Access-Control-Allow-Origin',
                value: '*',
              },
            ],
          },
          {
            source: 'file.js.map',
            headers: [
              {
                key: 'Access-Control-Allow-Origin',
                value: '*',
              },
            ],
          },
        ],
      })

[Ian Storm Taylor]

Tracked it down further up the stack, so not serve-handler's fault.