Remove more examples of deprecated iso_checksum_type in docs

Follow up to remove_iso_checksum_type

Signed-off-by: Jean-Francois Panisset <panisset@gmail.com>

examples/alicloud/local/centos.json

@@ -7,8 +7,7 @@
     "headless": "",
     "http_proxy": "{{env `http_proxy`}}",
     "https_proxy": "{{env `https_proxy`}}",
-    "iso_checksum": "0ca12fe5f28c2ceed4f4084b41ff8a0b",
-    "iso_checksum_type": "md5",
+    "iso_checksum": "md5:0ca12fe5f28c2ceed4f4084b41ff8a0b",
     "iso_name": "CentOS-6.8-x86_64-minimal.iso",
     "ks_path": "centos-6.8/ks.cfg",
     "memory": "512",

examples/ucloud/local/local.json

@@ -3,8 +3,7 @@
   "ucloud_private_key": "{{env `UCLOUD_PRIVATE_KEY`}}",
   "ucloud_project_id": "{{env `UCLOUD_PROJECT_ID`}}",
   "disk_size": "4096",
-  "iso_checksum": "0da4a1206e7642906e33c0f155d2f835",
-  "iso_checksum_type": "md5",
+  "iso_checksum": "md5:0da4a1206e7642906e33c0f155d2f835",
   "iso_name": "CentOS-6.10-x86_64-minimal.iso",
   "ks_path": "centos-6.10/ks.cfg",
   "mirror": "http://mirrors.ustc.edu.cn/centos",

website/pages/guides/automatic-operating-system-installs/autounattend_windows.mdx

@@ -80,8 +80,7 @@ installation so that Packer can connect using the winrm communicator:
   "type": "virtualbox-iso",
   "guest_os_type": "Windows2008_64",
   "iso_url": "https://download.microsoft.com/download/7/5/E/75EC4E54-5B02-42D6-8879-D8D3A25FBEF7/7601.17514.101119-1850_x64fre_server_eval_en-us-GRMSXEVAL_EN_DVD.iso",
-  "iso_checksum": "30832AD76CCFA4CE48CCB936EDEFE02079D42FB1DA32201BF9E3A880C8ED6312",
-  "iso_checksum_type": "sha256",
+  "iso_checksum": "sha256:30832AD76CCFA4CE48CCB936EDEFE02079D42FB1DA32201BF9E3A880C8ED6312",
   "shutdown_command": "shutdown /s /t 10 /f /d p:4:1 /c Packer_Provisioning_Shutdown",
   "guest_additions_mode": "attach",
   "floppy_files": ["./scripts/Autounattend.xml", "./scripts/openssh.ps1"],