Remove specific minimum version

Rephrased the version note to merely recommend a recent 2 version
without singling out a specific version.

Author: OliverSieweke

book/01-introduction/sections/installing.asc

@@ -6,9 +6,9 @@ You can either install it as a package or via another installer, or download the
 
 [NOTE]
 ====
-This book was written using Git version *2.8.0*.
-Though most of the commands we use should work even in ancient versions of Git, some of them might not or might act slightly differently if you're using an older version.
-Since Git is quite excellent at preserving backwards compatibility, any version after 2.8 should work just fine.
+This book was written using Git version 2.
+Since Git is quite excellent at preserving backwards compatibility, any recent version should work just fine.
+Though most of the commands we use should work even in ancient versions of Git, some of them might not or might act slightly differently.
 ====
 
 ==== Installing on Linux