chore: Remove Slack badge

README.md

@@ -40,7 +40,6 @@ Node <8 | <5.0                        | <57
 [![Windows x86](https://ci.appveyor.com/api/projects/status/22mjbk59kvd55m9y/branch/master?svg=true)](https://ci.appveyor.com/project/sass/node-sass/branch/master)
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 Node-sass is a library that provides binding for Node.js to [LibSass], the C version of the popular stylesheet preprocessor, Sass.