Travis: fix MacOS build

.npmrc

@@ -1 +1,2 @@
 engine-strict=true
+scripts-prepend-node-path=true

.travis.yml

@@ -13,8 +13,8 @@ matrix:
       language: generic
 
 cache:
+  yarn: false
   directories:
-    - node_modules
     - $HOME/.cache/electron
     - $HOME/.cache/electron-builder
 
@@ -33,10 +33,12 @@ script:
         electronuserland/builder:10 \
         /bin/bash -c "yarn && npm run release:linux"
     else
-      yarn && npm run release:mac
+      npm run release:mac
     fi
 before_cache:
   - rm -rf $HOME/.cache/electron-builder
+before_install:
+  - rm -rf node_modules
 
 branches:
   except: