Update references/links; fix CI; remove _wip folder (#71)

Author: nmheim

.github/workflows/CI.yml

@@ -10,7 +10,7 @@ jobs:
       fail-fast: false
       matrix:
         version:
-          - '1.6'
+          - '1.7'
           - 'nightly'
         os:
           - ubuntu-latest

README.md

@@ -5,10 +5,9 @@
 ---
 
 [![License](https://img.shields.io/badge/License-MIT-blue.svg)](https://github.com/JuliaTeachingCTU/Scientific-Programming-in-Julia/blob/master/LICENSE)
-[![Dev](https://img.shields.io/badge/docs-dev-blue.svg)](https://JuliaTeachingCTU.github.io/Scientific-Programming-in-Julia/dev)
 
 
 This repository contains all the course materials for the master course
 _**Scientific Programming in Julia**_ taught at the Czech Techincal University
 in Prague. You can find more information on the official
-[course website](https://juliateachingctu.github.io/Scientific-Programming-in-Julia/stable).
+[course website](https://juliateachingctu.github.io/Scientific-Programming-in-Julia/dev).