Merge branch 'nagisa_valentines' into 'master'

Make Nagisa's maid costume part of the Valentines set so that it is actually used.

See merge request spnati/spnati.gitlab.io!1345

opponents/nagisa/meta.xml

@@ -39,6 +39,6 @@
         <tag>student</tag>
     </tags>
     <alternates>
-         <costume folder="opponents/reskins/nagisa_maid_cafe/" img="0-happy.png">Maid Cafe</costume>
+         <costume folder="opponents/reskins/nagisa_maid_cafe/" img="0-happy.png" set="valentines">Maid Cafe</costume>
     </alternates>
 </opponent>