Update links to OctopusDeploy/Issues

[borland]

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Background

We renamed master to main in OctopusDeploy/Issues

Results

Updates doc links accordingly

How to review this PR

Quality :heavy_check_mark:

Pre-requisites

• [ ] I have read How we use GitHub Issues for help deciding when and where it's appropriate to make an issue.
• [ ] I have considered informing or consulting the right people, according to the ownership map.
• [ ] I have considered appropriate testing for my change.