Add Heroku pipelines support (#5660)

plugins/heroku/_heroku

@@ -45,6 +45,18 @@ _1st_arguments=(
   "logs\:drains":"manage syslog drains"
   "maintenance\:on":"put the app into maintenance mode"
   "maintenance\:off":"take the app out of maintenance mode"
+  "pipelines":"list pipelines you have access to"
+  "pipelines\:add":"add this app to a pipeline"
+  "pipelines\:create":"create a new pipeline"
+  "pipelines\:destroy":"destroy a pipeline"
+  "pipelines\:diff":"compares the latest release of this app to its downstream app(s)"
+  "pipelines\:info":"show list of apps in a pipeline"
+  "pipelines\:list":"list pipelines you have access to"
+  "pipelines\:open":"open a pipeline in dashboard"
+  "pipelines\:promote":"promote the latest release of this app to its downstream app(s)"
+  "pipelines\:remove":"remove this app from its pipeline"
+  "pipelines\:rename":"rename a pipeline"
+  "pipelines\:update":"update this app's stage in a pipeline"
   "pg\:credentials":"display the DATABASE credentials"
   "pg\:diagnose":"run diagnostics report on DATABASE"
   "pg\:info":"display database information"
@@ -131,6 +143,41 @@ case "$words[1]" in
       '(-t|--tail)'{-t,--tail}'[continually stream logs]' \
     )
     ;;
+  pipelines)
+    _command_args=(
+      '(--json)'--json'[output in json format]' \
+    )
+    ;;
+  pipelines:add)
+    _command_args=(
+      '(-s|--stage)'{-s,--stage}'[stage of first app in pipeline]' \
+    )
+    ;;
+  pipelines:create)
+    _command_args=(
+      '(-s|--stage)'{-s,--stage}'[stage of first app in pipeline]' \
+    )
+    ;;
+  pipelines:info)
+    _command_args=(
+      '(--json)'--json'[output in json format]' \
+    )
+    ;;
+  pipelines:list)
+    _command_args=(
+      '(--json)'--json'[output in json format]' \
+    )
+    ;;
+  pipelines:promote)
+    _command_args=(
+      '(-t|--to)'{-t,--to}'[comma separated list of apps to promote to]' \
+    )
+    ;;
+  pipelines:update)
+    _command_args=(
+      '(-s|--stage)'{-s,--stage}'[stage of first app in pipeline]' \
+    )
+    ;;
   pgbackups:capture)
     _command_args=(
       '(-e|--expire)'{-e,--expire}'[if no slots are available to capture, delete the oldest backup to make room]' \