feat: Add support for config_map volumes

[joekhoobyar]

Support config_map volumes

Add support for kubernetes config maps as volumes.

This is a great help in letting our runners include less copy-pasted code or data.

kind: pipeline
type: kubernetes
name: default

clone:
  disable: true

steps:
- name: write
  pull: if-not-exists
  image: alpine
  volumes:
  - name: shared
    path: /shared
  commands:
  - pwd
  - echo "hello" > /shared/greetings.txt

- name: read
  pull: if-not-exists
  image: alpine
  volumes:
  - name: shared
    path: /shared
  commands:
  - pwd
  - ls /shared
  - cat /shared/greetings.txt

volumes:
- name: shared
  config_map:
    name: received-data-claim
    default_mode: 420
    optional: false

[marko-gacesa]

@joekhoobyar thank you very much for this! Can you please create a PR in the doc repo (https://github.com/drone/docs) so we have the new feature documented? Thanks!

[joekhoobyar]

@joekhoobyar thank you very much for this! Can you please create a PR in the doc repo (https://github.com/drone/docs) so we have the new feature documented? Thanks!

Sure, @marko-gacesa , I'd be happy to.

i was also thinking of submitting another PR or two. Secrets mounting, and projected volume mounting. These would also help a lot.