plantuml: update .war download URL

The download URL for the .war was the same for all versions, being
updated evertime there's a new version.

Now plantuml team changed their release process to distribute each
release under a different URL, so we can just use the new URL.

https://github.com/plantuml/plantuml/issues/153

software/plantuml/software.cfg

@@ -31,9 +31,8 @@ output = ${buildout:directory}/${:_buildout_section_name_}
 
 [plantuml.war]
 recipe = slapos.recipe.build:download
-# XXX the war from sourceforge has no version in URL
-url = https://netcologne.dl.sourceforge.net/project/plantuml/plantuml.war#2018-10-21
-md5sum = f956cd28b18ec34740bb1757276f9641
+url = https://downloads.sourceforge.net/project/plantuml/1.2018.13/plantuml.1.2018.13.war
+md5sum = cda05c8163237de039d777c197b3d282
 
 [versions]
 slapos.recipe.template = 4.3