pyIEM 1.21.0 Release

API Changes

• Discontinue persisting text product into {mcd,mpd} table storage.
• Discontinue storage of text product into sigmets, use product_id instead.
• Raise IncompleteWebRequest exception when autoplot datetime parsing fails.

New Features

• Add _check_dueling_tropics VTEC check looking for TR+HU overlap (#930).
• Add IEMRE DOMAINS to support upcoming expansion.
• Add pyiem.grid.util.grid_smear to shift masked data to fill in missing.
• Allow iemapp(memcachexpire) to be a callable, called back with environ.
• Cross check WCNs against watch database storage for PDS status (#925).
• For iemapp if the memcachekey= callable returns None, the check of
  memcache is short circuited.
• Store product_id for PIREPs and do some faked AFOS assignments to help.
• Support SPC afternoon Day 3 outlook (cycle assigned as 20) (#936).
• Support VTEC significance addition of Extreme Heat (XH) (#953).

Bug Fixes

• Fix and refactor SPC saw parsing of watch replacement number.
• Pop kwargs fig on MapPlot.
• Use less confusing landing page at WPC for ERO.
• Use round instead of int to compute zonal stats grid navigation.