added thesis (citation-style-language#2291)

Author: edsu

acm-sigchi-proceedings.csl

@@ -129,7 +129,7 @@
       </group>
       <group suffix=".">
         <choose>
-          <if type="bill book graphic legal_case legislation motion_picture report song" match="any">
+          <if type="bill book graphic legal_case legislation motion_picture report song thesis" match="any">
             <text macro="book-publisher" suffix="."/>
           </if>
           <else-if type="paper-conference">