Update README for new release: 0.3.27

Author: crzbarcea

README.md

@@ -7,7 +7,7 @@
 Use this URL for the source of the module. See the usage examples below for more details.
 
 ```hcl
-github.com/pbs/terraform-aws-rds-module?ref=x.y.z
+github.com/pbs/terraform-aws-rds-module?ref=0.3.27
 ```
 
 ### Alternative Installation Methods
@@ -28,7 +28,7 @@ Integrate this module like so:
 
 ```hcl
 module "rds" {
-  source = "github.com/pbs/terraform-aws-rds-module?ref=x.y.z"
+  source = "github.com/pbs/terraform-aws-rds-module?ref=0.3.27"
 
   # Required Parameters
   private_hosted_zone = "example.local"
@@ -47,7 +47,7 @@ module "rds" {
 
 If this repo is added as a subtree, then the version of the module should be close to the version shown here:
 
-`x.y.z`
+`0.3.27`
 
 Note, however that subtrees can be altered as desired within repositories.