fix CI badge

Author: WhiffleFish

README.md

@@ -1,4 +1,4 @@
-[![Build Status](https://travis-ci.org/JuliaPOMDP/LocalApproximationValueIteration.jl.svg?branch=master)](https://travis-ci.org/JuliaPOMDP/LocalApproximationValueIteration.jl)
+[![CI](https://github.com/JuliaPOMDP/LocalApproximationValueIteration.jl/actions/workflows/CI.yml/badge.svg)](https://github.com/JuliaPOMDP/LocalApproximationValueIteration.jl/actions/workflows/CI.yml)
 [![codecov](https://codecov.io/github/JuliaPOMDP/LocalApproximationValueIteration.jl/branch/master/graph/badge.svg?token=he21c4XyeP)](https://codecov.io/github/JuliaPOMDP/LocalApproximationValueIteration.jl)
 
 # LocalApproximationValueIteration
@@ -93,4 +93,4 @@ The API for querying the final policy object is identical to `DiscreteValueItera
 ```julia
 v = value(approx_policy, s)  # returns the approximately optimal value for state s
 a = action(approx_policy, s) # returns the approximately optimal action for state s
-```
+```