Bump Swift version to 5.2 (#106)

* Bump Swift version to 5.2
* README: Update “Contributions and support” section

.travis.yml

@@ -3,7 +3,7 @@ language: generic
 sudo: required
 dist: trusty
 env:
-    - SWIFT_VERSION=5.0
+    - SWIFT_VERSION=5.2
 install:
     - eval "$(curl -sL https://swiftenv.fuller.li/install.sh)"
 script:

Package.swift

@@ -1,4 +1,4 @@
-// swift-tools-version:5.0
+// swift-tools-version:5.2
 
 /**
  *  Splash

README.md

@@ -3,7 +3,7 @@
 </p>
 
 <p align="center">
-    <img src="https://img.shields.io/badge/Swift-5.0-orange.svg" />
+    <img src="https://img.shields.io/badge/Swift-5.2-orange.svg" />
     <a href="https://swift.org/package-manager">
         <img src="https://img.shields.io/badge/spm-compatible-brightgreen.svg?style=flat" alt="Swift Package Manager" />
     </a>
@@ -27,6 +27,10 @@ Thanks to my good friend [Gui Rambo](https://twitter.com/_inside), you can [try
 
 👉 [splash.rambo.codes](https://splash.rambo.codes)
 
+If you're using [Publish](https://github.com/JohnSundell/Publish), then there's an official plugin that makes it easy to integrate Splash into your website:
+
+👉 [SplashPublishPlugin](https://github.com/JohnSundell/SplashPublishPlugin)
+
 If you're using Jekyll, there's also a custom ```{% splash %}``` tag available for the Liquid templating language.
 
 👉 [splashtag](https://github.com/mannberg/splashtag)
@@ -143,7 +147,7 @@ Splash is distributed as a Swift package, making it easy to install for use in s
 
 Splash supports both macOS and Linux.
 
-*Before you begin, make sure that you have a Swift 4.2-compatible toolchain installed (for example Xcode 10 if you're on a Mac).*
+*Before you begin, make sure that you have a Swift 5.2-compatible toolchain installed (for example Xcode 11.5 or later if you're on a Mac).*
 
 ### 📦 As a package
 
@@ -194,7 +198,7 @@ $ install .build/Release/SplashHTMLGen /usr/local/bin/SplashHTMLGen
 
 Splash is developed completely in the open, and your contributions are more than welcome. It's still a very new project, so I'm sure there are bugs to be found and improvements to be made - and hopefully we can work on those together as a community.
 
-You might notice that this project does not have GitHub issues enabled. That's because with Splash, I'm trying out a new 100% PR-based open source workflow. This is a bit of an experiment, so let's see how it works out.
+This project does not come with GitHub Issues-based support, and users are instead encouraged to become active participants in its continued development — by fixing any bugs that they encounter, or by improving the documentation wherever it's found to be lacking.
 
 To read more about suggested workflows when contributing to Splash, how to report bugs and feature requests, as well as technical details and an architectural overview - check out the [Contributing Guide](https://github.com/JohnSundell/Splash/blob/master/CONTRIBUTING.md).