fix: Pin libtorch home in CI.

Author: mchav

.github/workflows/ci.yml

@@ -23,6 +23,9 @@ jobs:
           ghc-version: ${{ matrix.ghc }}
           cabal-version: latest
 
+      - name: Set LIBTORCH_HOME
+        run: echo "LIBTORCH_HOME=$HOME/.cache/libtorch" >> $GITHUB_ENV
+
       - name: Configure
         run: |
           cat > cabal.project <<EOF
@@ -38,7 +41,9 @@ jobs:
       - name: Cache
         uses: actions/cache@v4
         with:
-          path: ${{ steps.setup.outputs.cabal-store }}
+          path: |
+            ${{ steps.setup.outputs.cabal-store }}
+            ${{ env.LIBTORCH_HOME }}
           key: ${{ runner.os }}-ghc-${{ matrix.ghc }}-${{ hashFiles('cabal.project.freeze') }}
           restore-keys: ${{ runner.os }}-ghc-${{ matrix.ghc }}-