release.sh: fix the builder-login detection (info output is multiline)

release.sh

@@ -46,7 +46,7 @@ cmd_build() {
   [ -z "$(git status --porcelain)" ] || die "working tree is dirty — commit first, the tag carries the git sha"
 
   local logged_in=0
-  if cloudron builder info 2>/dev/null | grep -viq "not logged in"; then logged_in=1; fi
+  if ! cloudron builder info 2>/dev/null | grep -qi "not logged in"; then logged_in=1; fi
 
   local authargs=()
   if [ -n "${REGISTRY_BUILD_TOKEN:-}" ]; then