fix(build): Bundle XML and CSL resources with bibtex package (#2201)

Author: alerque

build-aux/list-distfiles.sh.in

@@ -20,7 +20,9 @@ printf '%s =' SILEDATA
 finder core -name '*.lua' -not -name '*_spec.lua' -not -name 'version.lua' -not -name 'features.lua' -not -name 'pathsetup.lua'
 finder classes inputters languages outputters packages shapers types typesetters pagebuilders -name '*.lua' -not -name '*_spec.lua'
 finder classes languages packages -name '*.ftl'
+finder packages -name '*.csl'
 finder packages -name '*.svg'
+finder packages -name '*.xml'
 
 printf '\n\n%s =' LUALIBRARIES
 finder lua-libraries -name '*.lua'