add build status badge

Author: KristofferC

README.md

@@ -4,9 +4,9 @@ This package is part of the Julia standard library (stdlib).
 
 `LinearAlgebra.jl` provides functionality for performing linear algebra operations in Julia.
 
-| **Coverage**                    |
-|:-------------------------------:|
-| [![][codecov-img]][codecov-url] |
+| **Build Status**                    | **Coverage**                    |
+|:-------------------------------:|:-------------------------------:|
+[![Build status](https://badge.buildkite.com/4032f509b3a7354c8ce7b34b98c7496d66adc4504b0101cbcf.svg?branch=master)](https://buildkite.com/julialang/linearalgebra-dot-jl) | [![][codecov-img]][codecov-url] |
 
 [codecov-img]: https://codecov.io/gh/JuliaLang/LinearAlgebra.jl/branch/master/graph/badge.svg
 [codecov-url]: https://codecov.io/gh/JuliaLang/LinearAlgebra.jl