Update yarn version used on build machines

build/tfs/darwin/continuous-build-darwin.yml

@@ -4,7 +4,7 @@ steps:
     versionSpec: "8.9.1"
 - task: geeklearningio.gl-vsts-tasks-yarn.yarn-installer-task.YarnInstaller@2
   inputs:
-    versionSpec: "1.3.2"
+    versionSpec: "1.9.4"
 - script: |
     yarn
   displayName: Install Dependencies

build/tfs/darwin/product-build-darwin.yml

@@ -5,7 +5,7 @@ steps:
 
 - task: geeklearningio.gl-vsts-tasks-yarn.yarn-installer-task.YarnInstaller@2
   inputs:
-    versionSpec: "1.3.2"
+    versionSpec: "1.9.4"
 
 - script: |
     set -e

build/tfs/linux/continuous-build-linux.yml

@@ -14,7 +14,7 @@ steps:
     versionSpec: "8.9.1"
 - task: geeklearningio.gl-vsts-tasks-yarn.yarn-installer-task.YarnInstaller@2
   inputs:
-    versionSpec: "1.3.2"
+    versionSpec: "1.9.4"
 - script: |
     yarn
   displayName: Install Dependencies

build/tfs/linux/product-build-linux.yml

@@ -5,7 +5,7 @@ steps:
 
 - task: geeklearningio.gl-vsts-tasks-yarn.yarn-installer-task.YarnInstaller@2
   inputs:
-    versionSpec: "1.3.2"
+    versionSpec: "1.9.4"
 
 - script: |
     set -e

build/tfs/win32/continuous-build-win32.yml

@@ -4,7 +4,7 @@ steps:
     versionSpec: "8.9.1"
 - task: geeklearningio.gl-vsts-tasks-yarn.yarn-installer-task.YarnInstaller@2
   inputs:
-    versionSpec: "1.3.2"
+    versionSpec: "1.9.4"
 - powershell: |
     yarn
   displayName: Install Dependencies

build/tfs/win32/product-build-win32.yml

@@ -5,7 +5,7 @@ steps:
 
 - task: geeklearningio.gl-vsts-tasks-yarn.yarn-installer-task.YarnInstaller@2
   inputs:
-    versionSpec: "1.3.2"
+    versionSpec: "1.9.4"
 
 - powershell: |
     . build/tfs/win32/exec.ps1