Run CI on default branch (#100)

* Run CI on default branch

* Fixup links in readme, too

Author: LilithHafner

.github/workflows/CI.yml

@@ -3,7 +3,7 @@ on:
   pull_request:
   push:
     branches:
-      - master
+      - main
     tags: '*'
 jobs:
   test:

README.md

@@ -1,7 +1,7 @@
 # Sorting Algorithms
 
-[![Build status](https://github.com/JuliaLang/SortingAlgorithms.jl/workflows/CI/badge.svg)](https://github.com/JuliaLang/SortingAlgorithms.jl/actions?query=workflow%3ACI+branch%3Amaster)
-[![Coverage Status](https://codecov.io/github/JuliaCollections/SortingAlgorithms.jl/coverage.svg?branch=master)](https://codecov.io/github/JuliaCollections/SortingAlgorithms.jl?branch=master)
+[![Build status](https://github.com/JuliaLang/SortingAlgorithms.jl/workflows/CI/badge.svg)](https://github.com/JuliaLang/SortingAlgorithms.jl/actions?query=workflow%3ACI+branch%3Amain)
+[![Coverage Status](https://codecov.io/github/JuliaCollections/SortingAlgorithms.jl/coverage.svg?branch=main)](https://codecov.io/github/JuliaCollections/SortingAlgorithms.jl?branch=main)
 [![deps](https://juliahub.com/docs/SortingAlgorithms/deps.svg)](https://juliahub.com/ui/Packages/SortingAlgorithms/6dCmw?t=2)
 
 The `SortingAlgorithms` package provides four sorting algorithms that can be used with Julia's [standard sorting API](https://docs.julialang.org/en/v1/base/sort/):