Update the web app manifest file related configs

The specification for the manifest file for web applications was
recently updated¹ and it changed one of the recommended file extensions
from `.manifest` to the unique `.webmanifest`².

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

¹ w3c/manifest@0eecadd
² w3c/manifest#346

Author: alrra

lighttpd.conf

@@ -125,6 +125,7 @@ mimetype.assign = (
 
     ".webapp"        =>  "application/x-web-app-manifest+json",
     ".appcache"      =>  "text/cache-manifest",
+    ".webmanifest"   =>  "application/manifest+json",
 
 
   # Media files
@@ -289,6 +290,10 @@ $HTTP["url"] =~ ".(appcache|manifest|webapp)" {
     expire.url = ( "" => "access plus 0 seconds" )
 }
 
+$HTTP["url"] =~ ".webmanifest" {
+    expire.url = ( "" => "access plus 1 week" )
+}
+
 # Media
 $HTTP["url"] =~ ".(gif|jpg|jpeg|png|m4a|f4a|f4b|oga|ogg|webm)" {
     expire.url = ( "" => "access plus 1 months" )