improve node and yarn versions

Author: joaomoreno

azure-pipelines.yml

@@ -7,11 +7,11 @@ trigger:
 steps:
 - task: NodeTool@0
   inputs:
-    versionSpec: "10.15.1"
+    versionSpec: "8.x"
 
 - task: geeklearningio.gl-vsts-tasks-yarn.yarn-installer-task.YarnInstaller@2
   inputs:
-    versionSpec: "1.10.1"
+    versionSpec: "1.x"
 
 - script: yarn
   displayName: Install Dependencies