Update NuGet.Config by adding nuget online repository

Author: loic-lopez

.github/workflows/UMVC.Editor.Core.release.yml

@@ -88,7 +88,7 @@ jobs:
   Test_UMVC_Editor:
     name: Test UMVC.Editor 🧪
     runs-on: ubuntu-latest
-    container: gableroux/unity3d:2019.3.13f1
+    container: unityci/editor:ubuntu-2021.1.19f1-windows-mono-0
     needs: Build_UMVC_Core
     if: "!contains(github.event.head_commit.message, '[skip ci]')"
 
@@ -132,7 +132,7 @@ jobs:
   Build_UMVC_Editor:
     name: Build UMVC.Editor 🏗️
     runs-on: ubuntu-latest
-    container: gableroux/unity3d:2019.3.13f1
+    container: gableroux/unity3d:ubuntu-2021.1.19f1-windows-mono-0
     needs: Test_UMVC_Editor
     if: "!contains(github.event.head_commit.message, '[skip ci]')"
 

.github/workflows/UMVC.Editor.yml

@@ -11,7 +11,7 @@ jobs:
   test:
     name: Test UMVC.Editor 🧪
     runs-on: ubuntu-latest
-    container: gableroux/unity3d:2019.3.13f1
+    container: unityci/editor:ubuntu-2021.1.19f1-windows-mono-0
 
     steps:
       - name: Wait for build to succeed