restic version downgraded after package upgrade/reinstallation

[jj05]

Upgrading/reinstalling the restic package causes /usr/bin/restic to be overwritten.

After the version downgrade, backups/restores will fail if repository v2 is used, which isn't supported by the older versions

## To reproduce the issue:

Run docker run -it docker.io/ubuntu:22.04

apt-get update
apt-get -yy install restic ca-certificates
restic self-update
restic version # restic 0.15.1
apt-get -yy install --reinstall restic
restic version # restic 0.12.1

## Possible solutions

* Write the updated binary to /usr/local/bin/restic instead

* Disable self-update when installed from a DEB package

## Workaround:

Copy the binary to /usr/local/bin/restic and remove the Debian package

apt-get -yy install restic ca-certificates
cp /usr/bin/restic /usr/local/bin/restic
apt-get --purge autoremove restic
restic self-update

## Upstream

I've opened a bug on the restic upstream repo, and it was closed after saying it was a bug with the Debian package, and thus out of scope

https://github.com/restic/restic/issues/4237