remove WS2019 runner

Signed-off-by: Maksim An <maksiman@microsoft.com>

Author: anmaxvl

.github/workflows/ci.yml

@@ -273,10 +273,8 @@ jobs:
       fail-fast: false
       matrix:
         name:
-          [windows-2022, windows-2019]
+          [windows-2022]
         include:
-          - name: "windows-2019"
-            runner: [self-hosted, 1ES.Pool=containerplat-github-runner-pool-east-us-2, 1ES.ImageOverride=github-mms-ws2019-containers-enabled]
           - name: "windows-2022"
             runner: [self-hosted, 1ES.Pool=containerplat-github-runner-pool-east-us-2, 1ES.ImageOverride=github-mms-ws2022-containers-enabled]
     steps:
@@ -404,7 +402,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [windows-2019, windows-2022]
+        os: [windows-2022]
 
     steps:
       - name: Checkout hcsshim