Release v1.0

After almost a year with this code in production, all our backward
incompatible changes addressed, and much improved documentation,
we are now in a good place to call this "ready for everyone to use"

Signed-off-by: Daniel Magliola <danielmagliola@gocardless.com>

lib/prometheus/client/version.rb

@@ -2,6 +2,6 @@
 
 module Prometheus
   module Client
-    VERSION = '0.11.0-alpha.1'
+    VERSION = '1.0.0'
   end
 end