add some badges to readme (#38)

* Aqua
* CI
* Codecov
* PkgEval

The PkgEval badge will only start being active sometime after the
package gets registered, but I guess we might place it here right away.

Fixes #22

Author: nsajko

README.md

@@ -1,5 +1,10 @@
 ## `FixedSizeArrays.jl`
 
+[![Aqua QA](https://raw.githubusercontent.com/JuliaTesting/Aqua.jl/master/badge.svg)](https://github.com/JuliaTesting/Aqua.jl)
+[![Build Status](https://github.com/JuliaArrays/FixedSizeArrays.jl/actions/workflows/UnitTests.yml/badge.svg?branch=main)](https://github.com/JuliaArrays/FixedSizeArrays.jl/actions/workflows/UnitTests.yml?query=branch%3Amain)
+[![Coverage](https://codecov.io/gh/JuliaArrays/FixedSizeArrays.jl/branch/main/graph/badge.svg)](https://codecov.io/gh/JuliaArrays/FixedSizeArrays.jl)
+[![PkgEval](https://JuliaCI.github.io/NanosoldierReports/pkgeval_badges/F/FixedSizeArrays.svg)](https://JuliaCI.github.io/NanosoldierReports/pkgeval_badges/F/FixedSizeArrays.html)
+
 `FixedSizeArrays.jl` is a proof-of-concept package for the [Julia programming language](https://julialang.org/) which implements mutable fixed-size arrays, which means the lenght of the array is constant and is amenable to be [constant-propagated](https://en.wikipedia.org/wiki/Constant_folding) at compile-time when possible.
 This is an alternative implementation to [`MArray`](https://juliaarrays.github.io/StaticArrays.jl/stable/pages/api/#StaticArraysCore.MArray) from [`StaticArrays.jl`](https://github.com/JuliaArrays/StaticArrays.jl).