[Tests] on windows, test on 12.10, not 12.x;

Author: ljharb

appveyor.yml

@@ -1,7 +1,7 @@
 # Test against this version of Node.js
 environment:
   matrix:
-  - nodejs_version: "12"
+  - nodejs_version: "12.10.0"
   - nodejs_version: "10"
   - nodejs_version: "8"
   # - nodejs_version: "6"