[Testing] [Tooling] chore: replace `gocuke` & `go-mockdns` in go.mod

[bryanchriswhite]

Description

Add replace directives for gocuke and go-mockdns forks/releases until upstream PRs are merged. Includes TECHDEBT comments for removal.

Issue

Extracted from #753

Type of change

Please mark the relevant option(s):

• [ ] New feature, functionality or library
• [ ] Bug fix
• [ ] Code health or cleanup
• [ ] Major breaking change
• [ ] Documentation
• [x] Other: swapping test dependencies for our own forks/releases thereof

List of changes

• Replaced github.com/foxcpp/go-mockdns with github.com/pokt-network/go-mockdns v0.0.1
• Replaced github.com/regen-network/gocuke with github.com/pokt-network/gocuke v0.0.1

Testing

• [ ] make develop_test; if any code changes were made
• [ ] make test_e2e on k8s LocalNet; if any code changes were made
• [ ] e2e-devnet-test passes tests on DevNet; if any code was changed
• [ ] Docker Compose LocalNet; if any major functionality was changed or introduced
• [ ] k8s LocalNet; if any infrastructure or configuration changes were made

Required Checklist

• [x] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [ ] I have added, or updated, godoc format comments on touched members (see: tip.golang.org/doc/comment)
• [ ] I have tested my changes using the available tooling
• [ ] I have updated the corresponding CHANGELOG

If Applicable Checklist

• [ ] I have updated the corresponding README(s); local and/or global
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] I have added, or updated, mermaid.js diagrams in the corresponding README(s)
• [ ] I have added, or updated, documentation and mermaid.js diagrams in shared/docs/* if I updated shared/*README(s)