Update readme to address Lazy block syntax (#135)

The InertiaRails::Lazy object in addition to passing a lambda or proc
via a positional argument also accepts a block argument. This is another
idiomatic to pass proc-like behavior in Ruby and should be documented as
well.

Author: austenmadden

README.md

@@ -182,6 +182,9 @@ On the front end, Inertia supports the concept of "partial reloads" where only t
 
 ```ruby
   inertia_share some_data: InertiaRails.lazy(lambda { some_very_slow_method })
+
+  # Using a Ruby block syntax
+  inertia_share some_data: InertiaRails.lazy { some_very_slow_method }
 ```
 
 ### Routing