[DATALAD RUNCMD] Update datasets.datalad.org coverage (from 50TB to 240TB)

=== Do not change lines below ===
{
 "chain": [],
 "cmd": "sed -i -e s,50TB,240TB,g -e s,OpenfMRI,OpenNeuro,g 00-overview.md 01-shell-basics.md 02-vcs.md 03-packages.md 04-legalities.md 05-misc.md 11-wrap-up.md",
 "exit": 0,
 "extra_inputs": [],
 "inputs": [],
 "outputs": [],
 "pwd": "_episodes"
}
^^^ Do not change lines above ^^^

Author: yarikoptic

_episodes/02-vcs.md

@@ -307,7 +307,7 @@ The [DataLad] project relies on Git and git-annex to establish an
 integrated data monitoring, management, and distribution environment.
 As data distribution capitalizing on a number of "data
 crawlers" for existing data portals, it provides unified access to over
-50TB of data from various initiatives (such as CRCNS, OpenfMRI, etc.).
+240TB of data from various initiatives (such as CRCNS, OpenNeuro, etc.).
 
 > ## External teaching materials
 > - [The DataLad Handbook](https://handbook.datalad.org) is a code-along crash-course

_episodes/03-packages.md

@@ -164,7 +164,7 @@ Aggregation of multiple datasets is done via the
 and a dataset containing other datasets is called a
 [superdataset](http://docs.datalad.org/en/latest/glossary.html) in DataLad.
 One such super-dataset is provided from http://datasets.datalad.org and
-aggregates hundreds of neuroscience datasets over 50TB in size altogether.
+aggregates hundreds of neuroscience datasets over 240TB in size altogether.
 To learn about DataLad, please refer to the [VCS lesson:DataLad](../02-vcs/#datalad).