Remove the Travis and AppVeyor build status, which are no longer active

Author: msuchane

README.md

@@ -4,8 +4,6 @@
 [![Crates.io](https://img.shields.io/crates/d/newdoc)](https://crates.io/crates/newdoc)
 [![Crates.io](https://img.shields.io/crates/l/newdoc)](https://crates.io/crates/newdoc)
 
-[![Travis (.org)](https://img.shields.io/travis/redhat-documentation/newdoc)](https://travis-ci.org/github/redhat-documentation/newdoc)
-[![AppVeyor](https://img.shields.io/appveyor/build/mrksu/newdoc)](https://ci.appveyor.com/project/mrksu/newdoc)
 [![Copr build](https://copr.fedorainfracloud.org/coprs/mareksu/newdoc-rs/package/newdoc/status_image/last_build.png)](https://copr.fedorainfracloud.org/coprs/mareksu/newdoc-rs/package/newdoc/)
 
 The `newdoc` tool generates pre-populated module and assembly files formatted with AsciiDoc, which are used in Red Hat and Fedora documentation. The generated files follow the Modular Documentation guidelines: <https://redhat-documentation.github.io/modular-docs/>.