Merge pull request #127 from JuliaDiff/dpa/buildkite-badge

README: add Buildkite badge, and remove old badges

Author: ChrisRackauckas

README.md

@@ -1,8 +1,7 @@
 # SparseDiffTools.jl
 
 [![Join the chat at https://gitter.im/JuliaDiff/Lobby](https://badges.gitter.im/JuliaDiff/Lobby.svg)](https://gitter.im/JuliaDiff/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
-[![Build Status](https://travis-ci.com/JuliaDiff/SparseDiffTools.jl.svg?branch=master)](https://travis-ci.com/JuliaDiff/SparseDiffTools.jl)
-[![GitlabCI](https://gitlab.com/JuliaGPU/SparseDiffTools.jl/badges/master/pipeline.svg)](https://gitlab.com/JuliaGPU/SparseDiffTools.jl/pipelines)
+[![Build status](https://badge.buildkite.com/ea7df061e20328f60d3e0816d97d2d856166f2ea7030748cef.svg?branch=master)](https://buildkite.com/julialang/sparsedifftools-dot-jl)
 
 This package is for exploiting sparsity in Jacobians and Hessians to accelerate
 computations. Matrix-free Jacobian-vector product and Hessian-vector product