Bump up GoCD Version to 20.8.0
Bump up GoCD Version to 20.8.0

Signed-off-by: GoCD Build User <4578ec8179ef007597ca110be5c4cbfb0145b60b@googlegroups.com>

GaneshSPatil/gocd,GaneshSPatil/gocd,marques-work/gocd,Skarlso/gocd,gocd/gocd,ketan/gocd,Skarlso/gocd,GaneshSPatil/gocd,Skarlso/gocd,Skarlso/gocd,marques-work/gocd,ketan/gocd,ketan/gocd,gocd/gocd,Skarlso/gocd,ketan/gocd,marques-work/gocd,gocd/gocd,ketan/gocd,ketan/gocd,Skarlso/gocd,GaneshSPatil/gocd,GaneshSPatil/gocd,gocd/gocd,marques-work/gocd,marques-work/gocd,GaneshSPatil/gocd,gocd/gocd,gocd/gocd,marques-work/gocd