Use Lstat() Instead of Stat()

[midnightconman]

This PR switches the tar driver from using os.Stat() to os.Lstat()... this enables symlink file existence testing with the tar driver.

If tests are needed, please let me know... I verified functionality manually (via testing existence of symlinks in a docker image).

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[midnightconman]

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[nkubala]

@midnightconman thanks for the contribution! tests would be great :) could you add a unit test? it would also be great to show an example using this, if you think that's possible.

[nkubala]

@midnightconman any update here? I'd be happy to merge this with a test.

[charlyx]

@midnightconman Hi, do you need help with test? I'd be more than happy to help.

@nkubala How can I help? should I open a new PR with missing test?

[nkubala]

@charlyx thanks for jumping in. if @midnightconman can give you write access to their branch, you could simply update this PR and we could merge it, but i'm not sure that will happen in a timely manner.

if you'd like to open a PR with a test and reference it in this one, we can just merge both.