ci/travis: also cache $DEPS_DOWNLOAD_DIR

ref #5166

.travis.yml

@@ -121,6 +121,7 @@ cache:
   directories:
     - "$HOME/.cache/pip"
     - "$HOME/.cache/nvim-deps"
+    - "$HOME/.cache/nvim-deps-downloads"
 
 notifications:
   webhooks:

ci/before_cache.sh

@@ -15,6 +15,10 @@ rm -f "${HOME}/.cache/pip/selfcheck.json"
 if ended_successfully; then
   rm -rf "${HOME}/.cache/nvim-deps"
   mv "${DEPS_BUILD_DIR}" "${HOME}/.cache/nvim-deps"
+
+  rm -rf "${HOME}/.cache/nvim-deps-downloads"
+  mv "${DEPS_DOWNLOAD_DIR}" "${HOME}/.cache/nvim-deps-downloads"
+
   touch "${CACHE_MARKER}"
   echo "Updated third-party dependencies (timestamp: $(_stat "${CACHE_MARKER}"))."
 fi

ci/common/build.sh

@@ -27,11 +27,13 @@ build_deps() {
   fi
 
   mkdir -p "${DEPS_BUILD_DIR}"
+  mkdir -p "${DEPS_DOWNLOAD_DIR}"
 
   # Use cached dependencies if $CACHE_MARKER exists.
   if test -f "${CACHE_MARKER}" && ! test "${CACHE_ENABLE}" = "false" ; then
     echo "Using third-party dependencies from Travis cache (last update: $(_stat "${CACHE_MARKER}"))."
     cp -r "${HOME}/.cache/nvim-deps" "${DEPS_BUILD_DIR}"
+    cp -r "${HOME}/.cache/nvim-deps-downloads" "${DEPS_DOWNLOAD_DIR}"
   fi
 
   # Even if we're using cached dependencies, run CMake and make to