Add support for miniswhite when using TIFF output

lib/index.d.ts

@@ -1234,6 +1234,8 @@ declare namespace sharp {
         yres?: number | undefined;
         /** Reduce bitdepth to 1, 2 or 4 bit (optional, default 8) */
         bitdepth?: 1 | 2 | 4 | 8 | undefined;
+        /** Write 1-bit images as miniswhite (optional, default false) */
+        miniswhite?: boolean | undefined;
         /** Resolution unit options: inch, cm (optional, default 'inch') */
         resolutionUnit?: 'inch' | 'cm' | undefined;
     }