btrfs-progs: INSTALL: add minimal version of crypto libraries

Configure verifies the minimum version, make them explicit in the
installation docs.

Signed-off-by: David Sterba <dsterba@suse.com>

Author: kdave

INSTALL

@@ -18,9 +18,9 @@ Optionally, the checksums based on cryptographic hashes can be implemented by
 external libraries. Builtin implementations are provided in case the library
 dependencies are not desired.
 
-- libgcrypt
-- libsodium
-- libkcapi
+- libgcrypt >= 1.8.0
+- libsodium >= 1.0.4
+- libkcapi >= 1.0.0
 
 Optionally, multipath device detection requires libudev and running udev
 daemon, as it's the only source of the path information. Static build has a