feat: enable sync between new versions of inception and existing repos

[wtfzambo]

Fixes #59.

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Some context regarding the changes: I found two solutions to address this and both had drawbacks. I chose the one with the least drawback. Specifically:

• ❌ One solution keeps the template rendering as it was but requires some hacky nonsense to make copier update work properly. The reason is that when you run the update, it goes through the template rendering again. Since it was configured to output everything under a project_name folder, instead of updating the existing repo, it would create a subdirectory with the same name and the diffed files inside of it.
• ✅ The other solution changes the way the template rendering behaves: instead of generating the project in the project-name subfolder w.r.t. dst_path, it generates it at dst_path. Hence, creating a project folder is in the user's hands. In this case, copier update works as expected.