Add badge for Godbolt / Compiler Explorer [ci skip]

Author: martinmoene

README.md

@@ -1,6 +1,6 @@
 # string bare: string facilities for C++11 and later (In Progress)
 
-[![Language](https://img.shields.io/badge/C%2B%2B-11/14/17/20/23-blue.svg)](https://en.wikipedia.org/wiki/C%2B%2B#Standardization) [![License](https://img.shields.io/badge/license-BSL-blue.svg)](https://opensource.org/licenses/BSL-1.0) [![Build Status](https://github.com/martinmoene/string-bare/actions/workflows/ci.yml/badge.svg)](https://github.com/martinmoene/string-bare/actions/workflows/ci.yml) [![Version](https://badge.fury.io/gh/martinmoene%2Fstring-bare.svg)](https://github.com/martinmoene/string-bare/releases) [![download](https://img.shields.io/badge/latest-download-blue.svg)](https://github.com/martinmoene/string-bare/blob/master/include/nonstd/string.hpp) <!-- [![Conan](https://img.shields.io/badge/on-conan-blue.svg)](https://conan.io/center/string-bare) [![Try it on wandbox](https://img.shields.io/badge/on-wandbox-blue.svg)](https://wandbox.org/) [![Try it on godbolt online](https://img.shields.io/badge/on-godbolt-blue.svg)](https://godbolt.org/) -->
+[![Language](https://img.shields.io/badge/C%2B%2B-11/14/17/20/23-blue.svg)](https://en.wikipedia.org/wiki/C%2B%2B#Standardization) [![License](https://img.shields.io/badge/license-BSL-blue.svg)](https://opensource.org/licenses/BSL-1.0) [![Build Status](https://github.com/martinmoene/string-bare/actions/workflows/ci.yml/badge.svg)](https://github.com/martinmoene/string-bare/actions/workflows/ci.yml) [![Version](https://badge.fury.io/gh/martinmoene%2Fstring-bare.svg)](https://github.com/martinmoene/string-bare/releases) [![download](https://img.shields.io/badge/latest-download-blue.svg)](https://github.com/martinmoene/string-bare/blob/master/include/nonstd/string.hpp) <!-- [![Conan](https://img.shields.io/badge/on-conan-blue.svg)](https://conan.io/center/string-bare) [![Try it on wandbox](https://img.shields.io/badge/on-wandbox-blue.svg)](https://wandbox.org/) -->[![Try it on godbolt online](https://img.shields.io/badge/on-godbolt-blue.svg)](https://godbolt.org/z/6a5GWY8dP)
 
 Another attempt at a hopefully generally useful C++ string algorithm library.