Add script to install doctest

script/ci_install_deps.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+JOBS=4
+BUILD_TYPE=Debug
+
+set -eux
+
+git clone https://github.com/onqtam/doctest -b 2.4.4 --depth 1
+
+cmake -S doctest -B doctest/build \
+    -D CMAKE_BUILD_TYPE=${BUILD_TYPE} \
+    -D DOCTEST_WITH_MAIN_IN_STATIC_LIB=NO \
+    -D DOCTEST_WITH_TESTS=NO
+
+cmake --build doctest/build --config ${BUILD_TYPE} --target install -j ${JOBS}
+
+rm -rf doctest