[luacheck] update luacheck to 0.22.0

Author: mikz

Dockerfile

@@ -1,7 +1,7 @@
 FROM alpine:3.7
 
 LABEL maintainer="Michal Cichra <michal@cichra.cz>"
-ENV LUA_VERSION=5.3 LUACHECK_VERSION=0.21.2
+ENV LUA_VERSION=5.3 LUACHECK_VERSION=0.22.0
 
 WORKDIR /tmp
 COPY Gemfile* /tmp/