revert the mask to defualt name

Author: ehavazli

prep/NISAR_prep.ipynb

@@ -374,7 +374,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "out_mask = f\"{work_dir}/waterMask_v2.msk\"   # GeoTIFF file, just named .msk as requested\n",
+    "out_mask = f\"{work_dir}/waterMask.msk\"   # GeoTIFF file, just named .msk as requested\n",
     "res_m = 40                   # WorldCover is ~10m; NISAR is ~80m\n",
     "\n",
     "# Read EPSG from the first NISAR file\n",