Native support for piping stdout to stdin between commands

[zan-xhipe]

Description

I often find myself writing pipelines with various unix tools and it would be great if Task had native support for this. Adds a new attribute for a task called pipe that is mutually exclusive with cmds. It accepts an array of commands, same as cmds but it pipes stdout of each to stdin of the next.

An alternative would be to have a pipe: true option to enable this behaviour on cmds.

It would look something like this.

tasks:
  prepare:
    pipe:
      - aws logs filter-log-events --log-group-name {{.LOG_GROUP}} --filter-pattern REPORT --query 'events[*].message'
      - jq -R '.[]'
      - grep .
      - grep -v 'INIT_REPORT'
      - tr -du "[:alpha:]"
      - cut -f2-5
      - tr '\t' ','