Implementing stop feature on workflow

[patkivikram]

Description

This PR implements the stop functionality on the workflow. When stop is invoked on the workflow, dagger will invoke the stop method's implemented in the currently executing tasks

Type of Change

• [ ] Bug Fix
• [x ] New Feature
• [ ] Breaking Change
• [ ] Refactor
• [ ] Documentation
• [ ] Other (please describe)

Checklist

• [ x] I have read the contributing guidelines
• [ x] Existing issues have been referenced (where applicable)
• [x ] I have verified this change is not present in other open pull requests
• [ x] Functionality is documented
• [x ] All code style checks pass
• [ x] New code contribution is covered by automated tests
• [x ] All new and existing tests pass

[codecov[bot]]

Codecov Report

Merging #29 (1a85e09) into main (bc0d486) will increase coverage by 0.02%. The diff coverage is 93.33%.

@@            Coverage Diff             @@
##             main      #29      +/-   ##
==========================================
+ Coverage   86.66%   86.69%   +0.02%     
==========================================
  Files          12       12              
  Lines        1830     1841      +11     
  Branches      214      218       +4     
==========================================
+ Hits         1586     1596      +10     
  Misses        144      144              
- Partials      100      101       +1     

Impacted Files	Coverage Δ
dagger/tasks/task.py	80.03% <91.66%> (+0.24%)	:arrow_up:
dagger/__init__.py	100.00% <100.00%> (ø)
dagger/modeler/builder_helper.py	94.36% <100.00%> (ø)