Merge pull request #3384 from JuliaReach/schillic/update

Update reference to Gitter -> Zulip

README.md

@@ -3,7 +3,7 @@
 
 | **Introduction & Documentation** |**Status** |**Community** |**Version-specific Citation** | **License** |
 |:-----------------:|:---------------:|:------------:|:----------------------------:|:-----------:|
-| [![paper][paper-img]][paper-url] [![docs-dev][dev-img]][dev-url] | [![CI][ci-img]][ci-url] [![codecov][cov-img]][cov-url] | [![gitter][chat-img]][chat-url] | [![zenodo][doi-img]][doi-url] | [![license][lic-img]][lic-url] |
+| [![paper][paper-img]][paper-url] [![docs-dev][dev-img]][dev-url] | [![CI][ci-img]][ci-url] [![codecov][cov-img]][cov-url] | [![zulip][chat-img]][chat-url] | [![zenodo][doi-img]][doi-url] | [![license][lic-img]][lic-url] |
 
 [paper-img]: https://proceedings.juliacon.org/papers/10.21105/jcon.00097/status.svg
 [paper-url]: https://doi.org/10.21105/jcon.00097

docs/src/about.md

@@ -15,7 +15,7 @@ If you like this package, consider contributing!
 
 If you have written code and would like it to be peer reviewed and added to the library, you can [fork](https://help.github.com/en/articles/fork-a-repo) the repository and send a pull request (see below). Typical contributions include fixing a bug, adding a new feature or improving the documentation (either in source code or the [online manual](https://juliareach.github.io/LazySets.jl/latest/man/getting_started/)).
 
-You are also welcome to get in touch with us in the [JuliaReach gitter chat](https://gitter.im/JuliaReach/Lobby).
+You are also welcome to get in touch with us in the [JuliaReach Zulip chat](https://julialang.zulipchat.com/#narrow/stream/278609-juliareach).
 
 Below we detail some general comments about contributing to this package. The [JuliaReach Developer's Documentation](https://juliareach.github.io/JuliaReachDevDocs/latest/) describes coding guidelines; take a look when in doubt about the coding style that is expected for the code that is finally merged into the library.