Add free trial information to README

Added information about a 7-day free trial to the README.

Signed-off-by: Paul Hernandez <60959+phernandez@users.noreply.github.com>

Author: phernandez

README.md

@@ -14,7 +14,7 @@
 The open source project continues as always. Cloud just makes it work everywhere.
 
 [Sign up now →](https://basicmemory.com/beta)
-
+with a 7 day free trial
 
 # Basic Memory