ci-automation: Bump Azure amd64 and arm64 machine sizes to v6

Signed-off-by: James Le Cuirot <jlecuirot@microsoft.com>

Author: chewi

ci-automation/ci-config.env

@@ -148,8 +148,8 @@ AWS_PARALLEL="${PARALLEL_TESTS:-8}"
 
 # -- Azure --
 : ${AZURE_IMAGE_NAME:="flatcar_production_azure_image.vhd"}
-: ${AZURE_amd64_MACHINE_SIZE:="Standard_D2s_v4"}
-: ${AZURE_arm64_MACHINE_SIZE:="Standard_D2pls_v5"}
+: ${AZURE_amd64_MACHINE_SIZE:="Standard_D2s_v6"}
+: ${AZURE_arm64_MACHINE_SIZE:="Standard_D2pls_v6"}
 : ${AZURE_USE_GALLERY:=""}
 : ${AZURE_KOLA_VNET:=""}
 : ${AZURE_USE_PRIVATE_IPS:=true}