Update EOL versions (#10135)

### Summary of the changes

-

Fixes:

azure-pipelines-official.yml

@@ -382,7 +382,7 @@ extends:
             pool:
               ${{ if eq(variables['System.TeamProject'], 'public') }}:
                 name: NetCore-Public
-                demands: ImageOverride -equals Build.Ubuntu.1804.Amd64.Open
+                demands: ImageOverride -equals Build.Ubuntu.2004.Amd64.Open
               ${{ if eq(variables['System.TeamProject'], 'internal') }}:
                 name: $(DncEngInternalBuildPool)
                 demands: ImageOverride -equals 1es-ubuntu-2004-pt

azure-pipelines.yml

@@ -343,15 +343,15 @@ stages:
 
       - job: Linux
         container:
-          image: mcr.microsoft.com/dotnet-buildtools/prereqs:centos-stream8
+          image: mcr.microsoft.com/dotnet-buildtools/prereqs:cbl-mariner-2.0
           options: --init # This ensures all the stray defunct processes are reaped.
         pool:
           ${{ if eq(variables['System.TeamProject'], 'public') }}:
             name: NetCore-Public
-            demands: ImageOverride -equals Build.Ubuntu.1804.Amd64.Open
+            demands: ImageOverride -equals Build.Ubuntu.2004.Amd64.Open
           ${{ if eq(variables['System.TeamProject'], 'internal') }}:
             name: $(DncEngInternalBuildPool)
-            demands: ImageOverride -equals Build.Ubuntu.1804.Amd64
+            demands: ImageOverride -equals Build.Ubuntu.2004.Amd64
 
         strategy:
           matrix: