Add Latvian language localization (#301)

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>

Author: EPoikans

README.md

@@ -32,6 +32,7 @@ size or throughput. It is localized to:
 - Japanese
 - Klingon
 - Korean
+- Latvian
 - Norwegian
 - Persian
 - Polish

src/humanize/i18n.py

@@ -25,6 +25,7 @@
     "it_IT": ".",
     "pt_BR": ".",
     "hu_HU": " ",
+    "lv": " ",
 }
 
 # Mapping of locale to decimal separator
@@ -34,6 +35,7 @@
     "it_IT": ",",
     "pt_BR": ",",
     "hu_HU": ",",
+    "lv": ",",
 }