chore: bump versions in readme & docs

Author: ctrombley

README.md

@@ -29,7 +29,7 @@ Declare the provider in your configuration and `terraform init` will automatical
 terraform {
   required_providers {
     tfe = {
-      version = "~> 0.55.0"
+      version = "~> 0.56.0"
     }
   }
 }
@@ -45,7 +45,7 @@ The above snippet using `required_providers` is for Terraform 0.13+; if you are
 
 ```hcl
 provider "tfe" {
-  version = "~> 0.53.0"
+  version = "~> 0.56.0"
   ...
 }
 ```

website/docs/index.html.markdown

@@ -75,7 +75,7 @@ automatically installed by `terraform init` in the future:
 terraform {
   required_providers {
     tfe = {
-      version = "~> 0.55.0"
+      version = "~> 0.56.0"
     }
   }
 }
@@ -88,7 +88,7 @@ The above snippet using `required_providers` is for Terraform 0.13+; if you are
 
 ```hcl
 provider "tfe" {
-  version = "~> 0.53.0"
+  version = "~> 0.56.0"
   ...
 }
 ```
@@ -101,7 +101,7 @@ For more information on provider installation and constraining provider versions
 provider "tfe" {
   hostname = var.hostname # Optional, defaults to HCP Terraform `app.terraform.io`
   token    = var.token
-  version  = "~> 0.53.0"
+  version  = "~> 0.56.0"
 }
 
 # Create an organization