fix: Update docker files and docs

[vincentvdwal]

No description provided.

[vincentvdwal]

Currently I get an error trying to install the vapor package using Docker

error: Git command 'git -C /root/.cache/org.swift.swiftpm/repositories/vapor-ad7b9039 config --get remote.origin.url' failed: fatal: cannot change to '/root/.cache/org.swift.swiftpm/repositories/vapor-ad7b9039': No such file or directory
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failed to solve: process "/bin/sh -c swift package resolve" did not complete successfully: exit code: 1

Don't know how to solve that one