Update MicroBuild to v4

Author: ViktorHofer

eng/pipelines/build-PR.yml

@@ -47,7 +47,7 @@ jobs:
     - template: /eng/common/templates/steps/enable-internal-runtimes.yml
 
     - ${{ if ne(variables['System.TeamProject'], 'public') }}:
-      - task: MicroBuildSigningPlugin@2
+      - task: MicroBuildSigningPlugin@4
         displayName: Install MicroBuild plugin for Signing
         inputs:
           signType: $(_SignType)

eng/pipelines/build.yml

@@ -51,7 +51,7 @@ jobs:
   - template: /eng/common/templates-official/steps/enable-internal-sources.yml
   - template: /eng/common/templates-official/steps/enable-internal-runtimes.yml
 
-  - task: MicroBuildSigningPlugin@2
+  - task: MicroBuildSigningPlugin@4
     displayName: Install MicroBuild plugin for Signing
     inputs:
       signType: $(_SignType)