Add "require" metadata

src/elektra/redshift.ini

@@ -4,7 +4,7 @@
 ; TODO:
 ; 1. revise hierarchy, naming and types to make redshift config files easier to read and use and less error-prone. breaks backwards-compatibility.
 ; 2. after 1.: split up colon-separated options for location-providers and adjustment-methods into separate CLI arguments.
-; 3. after 1. and 2.: add properties "required", "default", etc.
+; 3. after 1. and 2.: add properties "require", "default", etc.
 ; 4. after 1. and 2.: add command line arguments to specification
 ; 5. after 1. and 2.: add enum values
 
@@ -82,14 +82,17 @@ check/enum/#3 = randr
 check/enum/#4 = vidmode
 check/enum/#5 = w32gdi
 description = The method used to adjust screen color temperature.
+require =
 
 [redshift/location-provider]
 type = string
 check/enum = #2
 check/enum/#0 = corelocation
 check/enum/#1 = geoclue2
 check/enum/#2 = manual
+require =
 description = The location provider. Used to establish whether it is currently daytime or nighttime.
+require =
 
 type = string
 check/date = ISO8601