CI: fix cached LTS map not setting resolver [kick 11]

.github/workflows/stack-test.yml

@@ -85,11 +85,6 @@ jobs:
     - name: ~/.stack cache diagnostics
       run: du -csh -t 64k ~/.stack/*
 
-    - name: Configure Stack
-      run: |
-        stack config set system-ghc true --global
-        stack config set install-ghc false --global
-
     #-- for the matrix, we'll need a map GHC version -> Stack LTS resolver
     - name: Cached LTS-GHC map
       id: ltsmap
@@ -102,13 +97,19 @@ jobs:
       run: |
         timeout 50 .github/scripts/stackage-lts-map.py \
           | sort -n | tee lts-resolver-map.yaml
+
+    - name: Configure Stack
+      run: |
+        #-- set resolver tag based on GHC version from the matrix
         selected="$(yq '.["${{ matrix.ghc }}"]' lts-resolver-map.yaml)"
         test -z $selected -o $selected == null && {
           echo "Could not find LTS snapshot for GHC version ${{ matrix.ghc }}"
           echo "Version map:"; cat lts-resolver-map.yaml
           exit 1
         } >&2
         stack config set resolver $selected
+        stack config set system-ghc true --global
+        stack config set install-ghc false --global
 
     #-- not much deps in this package; however Cabal is a large one. cache, too