ci: use cached stack

Author: simonmichael

.github/workflows/ci.yml

@@ -78,8 +78,8 @@ jobs:
       run: |
         mkdir -p ~/.local/bin
         export PATH=~/.local/bin:$PATH
-        curl -sL https://get.haskellstack.org/stable/linux-x86_64.tar.gz | tar xz --wildcards --strip-components=1 -C ~/.local/bin '*/stack'; chmod a+x ~/.local/bin/stack
-        # if [[ ! -x ~/.local/bin/stack ]]; then curl -sL https://get.haskellstack.org/stable/linux-x86_64.tar.gz | tar xz --wildcards --strip-components=1 -C ~/.local/bin '*/stack'; chmod a+x ~/.local/bin/stack; fi
+        # curl -sL https://get.haskellstack.org/stable/linux-x86_64.tar.gz | tar xz --wildcards --strip-components=1 -C ~/.local/bin '*/stack'; chmod a+x ~/.local/bin/stack
+        if [[ ! -x ~/.local/bin/stack ]]; then curl -sL https://get.haskellstack.org/stable/linux-x86_64.tar.gz | tar xz --wildcards --strip-components=1 -C ~/.local/bin '*/stack'; chmod a+x ~/.local/bin/stack; fi
         stack --version
 
     - name: Install GHC