prepare v0.3.0 (#28)

Signed-off-by: Yoan Blanc <yblanc@edgelab.ch>

Author: greut

README.md

@@ -17,7 +17,7 @@ In particular:
 
 ```hcl
 module "my_database" {
-  source = "git@github.com:edgelaboratories/terraform-mysql-db?ref=v0.2.3"
+  source = "git@github.com:edgelaboratories/terraform-mysql-db?ref=v0.3.0"
 
   database = "my-database"
 
@@ -28,8 +28,8 @@ module "my_database" {
   plaintext_password = "a very hard to guess password"
 
   # Default values are utf8mb4 and utf8mb4_unicode_ci
-  default_character_set = "utf8"
-  default_collation     = "utf8_unicode_ci"
+  default_character_set = "utf8mb3"
+  default_collation     = "utf8mb3_unicode_ci"
 
   # Optional
   vault_backend_path       = "mysql/my-cluster"
@@ -42,7 +42,7 @@ You can provide extra permissions for `all-privileges` or `read-only` roles with
 
 ```hcl
 module "my_database" {
-  source = "git@github.com:edgelaboratories/terraform-mysql-db?ref=v0.2.3"
+  source = "git@github.com:edgelaboratories/terraform-mysql-db?ref=v0.3.0"
 
   database = "my-database"