v0.9.1: Fix errors reported by shellcheck.

One of these is crucial to properly display outdated packages.

v0.9

Use a pywal color for outdated packages.

v0.8

Mention -Q in "Troubleshooting" section.

v0.7

Use NODE instead of VNODE on Void.

v0.6

Update screenshots.

v0.5

Document the highlighting.

v0.4

Add -c option.

v0.3

Change the screenshot.

v0.2

Hardwrap the contents of the README.

v0.1

Make the messages about used backends consistent.