chore: cache based on pnpm-lock.yaml

Author: Kelly Selden

appveyor.yml

@@ -25,7 +25,7 @@ test_script:
 
 # http://help.appveyor.com/discussions/questions/1310-delete-cache
 cache:
-  - node_modules -> package.json
+  - node_modules -> pnpm-lock.yaml
 
 # Don't actually build.
 build: off