update workflow

Author: joneugster

.github/workflows/test.yml

@@ -32,16 +32,33 @@ jobs:
           build: true
           test: false
           lint: false
-      - name: install elan
+
+
+      - name: install elan (Windows)
         if: matrix.os == 'windows-latest'
         run: |
           curl -O --location https://raw.githubusercontent.com/leanprover/elan/master/elan-init.ps1
           echo 1 | powershell -ExecutionPolicy Bypass -f elan-init.ps1
           del elan-init.ps1
-          (Resolve-Path ~/.elan/bin).Path >> $Env:GITHUB_PATH
-          cd demo\server\LeanProject
+        shell: pwsh
+
+      - name: add elan to PATH (Windows)
+        if: matrix.os == 'windows-latest'
+        run: (Resolve-Path ~/.elan/bin).Path >> $Env:GITHUB_PATH
+        shell: pwsh
+
+      - name: get mathlib cache
+        if: matrix.os == 'windows-latest'
+        run: lake exe cache get
+        shell: pwsh
+
+      - name: run lake build (Windows)
+        if: matrix.os == 'windows-latest'
+        run: |
+          CD demo\server\LeanProject
           lake build
         shell: pwsh
+
       # - name: install elan (Windows)
       #   if: matrix.os == 'windows-latest'
       #   run: |