Add weather zone hkz000 for Hong Kong Observatory

Thanks to Bill Agee for suggesting the Hong Kong Observatory's
weather forecast page. A custom filter is implemented to strip the
forecast text from the HTML page in which it is embedded (if anyone
finds a plaintext version published at an alternate URL, let me know
and I'll rip out the extra routine).

zones

@@ -20,7 +20,7 @@
 # ab78f945488371035514fc2c14e4679a 2020-05-24 airports.csv
 #
 # ...and these manually-generated or hand-compiled adjustments:
-# aadcf8801156f29dc5c622bb5e874e88 2020-05-24 overrides.conf
+# 298b10d8d6f5a4a41b2eb0c356766427 2020-05-24 overrides.conf
 # ab8545489a62124779edf7214a619325 2020-05-24 slist
 # 12c84e28cdb6da9eeba12b5a4af034b0 2020-05-24 zlist
 
@@ -14710,6 +14710,13 @@ station = ('phsf', 0.0040525)
 urgent_weather_message = https://tgftp.nws.noaa.gov/data/watches_warnings/non_precip/hi/hiz028.txt
 zone_forecast = https://tgftp.nws.noaa.gov/data/forecasts/zone/hi/hiz028.txt
 
+[hkz000]
+centroid = (0.3897902, 1.9928751)
+comment = suggested by Bill Agee
+description = Hong Kong Observatory
+station = ('vhhh', 0.0000000)
+zone_forecast = https://www.hko.gov.hk/textonly/v2/forecast/nday.htm
+
 [iaz001]
 centroid = (0.7571326, -1.6791865)
 coastal_flood_statement = https://tgftp.nws.noaa.gov/data/watches_warnings/flood/coastal/ia/iaz001.txt