Concourse: basic support for 'tags' attribute

vscode-extensions/vscode-concourse/src/main/java/org/springframework/ide/vscode/concourse/PipelineYmlSchema.java

@@ -135,6 +135,7 @@ public class PipelineYmlSchema implements YamlSchema {
 		prop(step, "on_failure", step);
 		prop(step, "ensure", step);
 		prop(step, "attempts", t_strictly_pos_integer);
+		prop(step, "tags", t_strings);
 		
 		YBeanType resource = f.ybean("Resource");
 		prop(resource, "name", t_ne_string);

vscode-extensions/vscode-concourse/src/main/resources/desc/Step/tags.md

@@ -0,0 +1,9 @@
+Perform a step on certain workers.
+
+Any step can be directed at a pool of workers for a given set of tags, by adding the `tags` attribute to it.
+
+	tags: [string]
+
+*Optional. Default* `[]`. The tags by which to match workers.
+
+For example, if `[a, b]` is specified, only workers advertising the `a` and `b` tags (or any others) will be used for running the step.