Bug fix: Stat block deprecation to better handle SVG attributes

• BU Stats Block: 5.7 upgrade related changes to SVG attributes caused block validation failures. This fixes it by adding a block deprecation to cover the previous way WP handled SVG elements in 5.4 and added attributes to the SVG element that are no longer added in 5.7. Fixes: bu-ist/bu-stats#106

What's Changed

• Add NPM Publishing instructions to README by @acketon in #391
• 5.7 bug stat block deprecation by @acketon in #394

Full Changelog: 0.4.0...0.4.1