Mention New Feature in release notes

Portable Git [can now be run from a RAM
disk](git-for-windows/git#2493), too.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

ReleaseNotes.md

@@ -39,6 +39,7 @@ This package contains software from a number of other projects including Bash, z
 
 * The Portable version of Git for Windows [now defaults to turning on the FSCache](https://github.com/git-for-windows/git/issues/2467) just like the installer does.
 * Comes with [Git LFS v2.10.0](https://github.com/git-lfs/git-lfs/releases/tag/v2.10.0).
+* Portable Git [can now be run from a RAM disk](https://github.com/git-for-windows/git/issues/2493), too.
 
 ### Bug Fixes