Fix dead link in CONTRIBUTING.md (#1044)

Author: kimsey0

CONTRIBUTING.md

@@ -11,7 +11,7 @@ An example of a common Meson/Ninja environment is described next.
 Thanks to David Seifert (@SoapGentoo), we (the maintainers) now use
 [meson](http://mesonbuild.com/) and [ninja](https://ninja-build.org/) to build
 for debugging, as well as for continuous integration (see
-[`./travis_scripts/meson_builder.sh`](./travis_scripts/meson_builder.sh) ). Other systems may work, but minor
+[`./.travis_scripts/meson_builder.sh`](./.travis_scripts/meson_builder.sh) ). Other systems may work, but minor
 things like version strings might break.
 
 First, install both meson (which requires Python3) and ninja.