feat(rulesets): add instance key to ruleset

[wsan3]

Description

• Add instance key to ruleset tag
• Enable steps to match and run on certain instances (e.g. dev vs prod)

Example

version: "1"

steps:
  - name: run step on production instance
    ruleset:
      event: push
      branch: main
      instance: https://octocat.prod.github.com
    image: alpine
    commands:
      - echo "this step ran on a production instance"

Related

go-vela/community#803

[codecov]

Codecov Report

Attention: Patch coverage is 93.54839% with 2 lines in your changes missing coverage. Please review.

Project coverage is 96.05%. Comparing base (75a4808) to head (94492cc).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #384      +/-   ##
==========================================
- Coverage   96.08%   96.05%   -0.03%     
==========================================
  Files          69       69              
  Lines        5365     5375      +10     
==========================================
+ Hits         5155     5163       +8     
- Misses        136      137       +1     
- Partials       74       75       +1     

Files	Coverage Δ
pipeline/container.go	81.45% <100.00%> (+0.24%)	⬆️
yaml/ruleset.go	100.00% <100.00%> (ø)
pipeline/ruleset.go	80.58% <71.42%> (-1.24%)	⬇️