Remove fetch includes as it is no longer required

fetch-includes.sh

diff --git a/fetch-includes.sh b/fetch-includes.sh
deleted file mode 100755
index 46f7adc..0000000
--- a/fetch-includes.sh
+++ /dev/null
@@ -1,8 +0,0 @@
-#!/usr/bin/env bash
-
-mkdir -p ./includes
-rm -rf ./includes/*
-
-git clone --branch v1.1.0 --depth=1 https://github.com/Tencent/rapidjson.git ./includes/rapidjson
-git clone --branch master --depth=1 https://github.com/louisdx/cxx-prettyprint.git ./includes/prettyprint
-git clone --branch master --depth=1 https://github.com/catchorg/Catch2.git ./includes/catch