[release/8.0] Update MicroBuild to v4 (#12724)

Upgrade MicroBuild to v4

Author: lonitra

eng/pipelines/build-PR.yml

@@ -49,7 +49,7 @@ jobs:
         env:
           Token: $(dn-bot-dnceng-artifact-feeds-rw)
 
-      - task: MicroBuildSigningPlugin@2
+      - task: MicroBuildSigningPlugin@4
         displayName: Install MicroBuild plugin for Signing
         inputs:
           signType: $(_SignType)

eng/pipelines/build.yml

@@ -56,7 +56,7 @@ jobs:
     env:
       Token: $(dn-bot-dnceng-artifact-feeds-rw)
 
-  - task: MicroBuildSigningPlugin@2
+  - task: MicroBuildSigningPlugin@4
     displayName: Install MicroBuild plugin for Signing
     inputs:
       signType: $(_SignType)