enhance(templates): inject template name as variable

[ecrupper]

Example pipeline:

.vela.yml

version: "1"

metadata:
  render_inline: true

templates:
  - name: example
    source: example.yml
    type: file

example.yml

metadata:
  template: true

stages:
  wait:
    steps:
      - name: run
        image: alpine
        commands:
          - sleep 20
          - printenv

  test:
    needs: [ wait ]
    steps:
      - name: run
        image: alpine
        commands:
          - echo "Hello World"

Due to the fact that the steps and stages get modified to include the template name, this configuration will not work due to wait stage being transformed to example_wait. With this change, that part can be modified to

needs: [{{ .VELA_TEMPLATE_NAME }}_wait]

This is beneficial to developing widely used templates without instructing all adopters to use the same template name.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 63.26%. Comparing base (5706d0f) to head (53b7b36).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1096      +/-   ##
==========================================
+ Coverage   63.24%   63.26%   +0.02%     
==========================================
  Files         348      348              
  Lines       10594    10600       +6     
==========================================
+ Hits         6700     6706       +6     
  Misses       3409     3409              
  Partials      485      485              

Files	Coverage Δ
compiler/native/compile.go	69.58% <100.00%> (+0.35%)	⬆️
compiler/native/expand.go	68.68% <100.00%> (+0.52%)	⬆️

[KellyMerrick]

lgtm