0.17.2

A small maintenance release which makes indicatif more portable and fixes some minor regressions.

• Use portable-atomic to fix build on some 32-bit platforms (#484, thanks to @messense)
• Implement multi-line progress message support (#443, thanks to @happenslol)
• Reset estimator of progress rate on backwards movement (#483, thanks to @rlee287)
• Fix percent initial value when there is no length (#491, thanks to @devmatteini)
• Bumped the MSRV to 1.56 (#482)

On behalf of @djc and @chris-laplante, thanks to all contributors!