Updated checklist for QA managers

[SilkeSchomann]

Description of work

Added instruction to QA manager checklist for ensuring that both conda and non-conda installations are covered for all operating systems.

There is no associated issue.

To test:

Check that the new instruction makes sense and that grammar and spelling are correct.

This does not require release notes because fit is an update of the developer documentation.

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Reviewer

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Code Review

• Is the code of an acceptable quality?
• Does the code conform to the coding standards?
• Are the unit tests small and test the class in isolation?
• If there is GUI work does it follow the GUI standards?
• If there are changes in the release notes then do they describe the changes appropriately?
• Do the release notes conform to the release notes guide?

Functional Tests

• Do changes function as described? Add comments below that describe the tests performed?
• Do the changes handle unexpected situations, e.g. bad input?
• Has the relevant (user and developer) documentation been added/updated?

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[rbauststfc]

I've built the dev-docs-html target and the new bullet point renders well. The new instruction is written clearly and is easy to understand.