nutriverse/zscorer: zscorer v0.3.1

Fourth release of zscorer. In this release:

• fixed an issue with wrong URLs in README documentation.

• fixed an issue when calculating BMI-for-age where measurements are 0 resulting in error rather than providing an NA value. Now, when values for measurements are 0, the zscore produced is NA.

• updated MUAC for age to allow for calculation for children up to 19 years old based on article by Jay Berkeley and colleagues.

• updated Shiny app and added a vignette showing how to use the Shiny app

• updated documentation to reflect editions and additions