Fix typo

`requried` -> `required`

maintainers/this-month-in-nix-docs/README.md

@@ -8,7 +8,7 @@ $ ./make-post.sh <from YYYY-MM-DD> <to YYYY-MM-DD> > new-post.md
 
 After this invocation a template post (`new-post.md`) will be filled out with the GitHub query results formatted as markdown at the end of the file.
 
-There is some post-processing requried:
+There is some post-processing required:
 - Fill in the number and year/month at the top of the post.
 - Manually check the RFCs for relevance
 - Remove the "Tracking Issues" section, it's there for your convenience while writing.