Add install-only test job and fix action.yml

action.yml

@@ -11,17 +11,17 @@ inputs:
     description: 'GoReleaser version'
     default: 'latest'
     required: false
-  install-only:
-    description: 'Just install GoReleaser'
-    default: 'false'
-    required: false
   args:
     description: 'Arguments to pass to GoReleaser'
-    required: true # not required when install-only=true
+    required: false
   workdir:
     description: 'Working directory (below repository root)'
     default: '.'
     required: false
+  install-only:
+    description: 'Just install GoReleaser'
+    default: 'false'
+    required: false
 
 runs:
   using: 'node12'