bug 1737691: update rust Docker image and minidump-stackwalk version
bug 1737691: update rust Docker image and minidump-stackwalk version

This updates the rust Docker image we use to build minidump-stackwalk
to 1.56.1.

It also updates minidump-stackwalk to 0.9.2 which picks up a bunch of
fixes.

https://github.com/luser/rust-minidump/blob/master/RELEASES.md#version-092-2021-11-10

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