Enable caching for tests

Author: hasufell

.github/workflows/test.yml

@@ -46,6 +46,7 @@ jobs:
           mkdir -p test-workspace/bin/
           export GHCUP_INSTALL_BASE_PREFIX=$(pwd)/test-workspace/bin
           echo $XDG_BIN_HOME $GHCUP_INSTALL_BASE_PREFIX
+          ghcup config set cache true
           ghcup --no-verbose prefetch hls 1.4.0
           ghcup --no-verbose prefetch hls latest
         shell: bash