ci: fix appveyor syntax error

appveyor.yml

@@ -1,12 +1,16 @@
 # Test against the latest version of this Node.js version
 environment:
   nodejs_version: "Current"
- cache:
+
+cache:
   - 'node_modules -> yarn.lock'
   - '%LOCALAPPDATA%\\Yarn -> yarn.lock'
- image: Visual Studio 2017
- shallow_clone: true
- # Install scripts. (runs after repo cloning)
+
+image: Visual Studio 2017
+
+shallow_clone: true
+
+# Install scripts. (runs after repo cloning)
 install:
   # Get the latest stable version of Node.js or io.js
   - ps: Install-Product node $env:nodejs_version
@@ -16,7 +20,8 @@ install:
   - yarn lerna link
   # Build packages
   - yarn build
- # Post-install test scripts.
+
+# Post-install test scripts.
 test_script:
   # Output useful info for debugging.
   - node --version
@@ -25,7 +30,9 @@ test_script:
   # run tests
   - yarn test:fixtures -w=2
   - yarn test:unit -w=2
- # Don't actually build.
+
+# Don't actually build.
 build: off
- # Do not build feature branch with open Pull Requests
+
+# Do not build feature branch with open Pull Requests
 skip_branch_with_pr: true