README.md: Add minimum lvm version
Any lvm version >=  2.02.163 which was released 10 August 2016
should work.
@@ -23,6 +23,7 @@ Supported environments
- Kubernetes: 1.24, 1.23, 1.22
- Node OS: Linux with LVM2 (*1)
- Filesystems: ext4, xfs, btrfs(experimental)
+- lvm version 2.02.163 or later (adds JSON output support)
*1 The host's Linux Kernel must be v4.9 or later which supports `rmapbt` and `reflink`, if you use xfs filesystem with an official docker image.
