readme: update the disk requirement to 2.5TB (#1642)

README.md

@@ -110,7 +110,7 @@ on how you can run your own `geth` instance.
 
 The hardware must meet certain requirements to run a full node on mainnet:
 - VPS running recent versions of Mac OS X, Linux, or Windows.
-- IMPORTANT 2 TB of free disk space, solid-state drive(SSD), gp3, 8k IOPS, 250 MB/S throughput, read latency <1ms. (if node is started with snap sync, it will need NVMe SSD)
+- IMPORTANT 2.5 TB(May 2023) of free disk space, solid-state drive(SSD), gp3, 8k IOPS, 250 MB/S throughput, read latency <1ms. (if node is started with snap sync, it will need NVMe SSD)
 - 16 cores of CPU and 64 GB of memory (RAM)
 - Suggest m5zn.3xlarge instance type on AWS, c2-standard-16 on Google cloud.
 - A broadband Internet connection with upload/download speeds of 5 MB/S