chore: add OpenTofu references to docs

CONTRIBUTING.md

@@ -2,7 +2,8 @@
 
 ## Requirements
 
-- [Terraform](https://developer.hashicorp.com/terraform/downloads) >= 1.0
+- [Terraform](https://developer.hashicorp.com/terraform/install) >= 1.0
+- [OpenTofu](https://opentofu.org/docs/intro/install/) >= 1.6
 - [Go](https://golang.org/doc/install) >= 1.23
 
 ## Building the Provider
@@ -31,7 +32,7 @@ terraform-provider-forgejo/
 This provider uses [Go modules](https://github.com/golang/go/wiki/Modules).
 Please see the Go documentation for the most up to date information about using Go modules.
 
-To add a new dependency `github.com/author/dependency` to your Terraform provider:
+To add a new dependency `github.com/author/dependency` to your Terraform/OpenTofu provider:
 
 ```shell
 go get github.com/author/dependency

README.md

@@ -1,10 +1,10 @@
 # Terraform Provider for Forgejo
 
-This repository contains a [Terraform](https://www.terraform.io/) provider for [Forgejo](https://forgejo.org/) — self-hosted lightweight software forge.
+This repository contains a [Terraform](https://www.terraform.io/) and [OpenTofu](https://opentofu.org/) provider for [Forgejo](https://forgejo.org/) — self-hosted lightweight software forge.
 
 ## Contents
 
-The Forgejo Terraform Provider allows managing resources within Forgejo. It is in an **early** stage and currently provides the following...
+The Forgejo Terraform/OpenTofu Provider allows managing resources within Forgejo. It is in an **early** stage and currently provides the following...
 
 Resources:
 
@@ -22,7 +22,7 @@ Data Sources:
 
 ## Using the Provider
 
-Import the provider into your Terraform configuration:
+Import the provider into your Terraform/OpenTofu configuration:
 
 ```terraform
 terraform {
@@ -71,7 +71,7 @@ provider "forgejo" {
 ```
 
 > **Important**: The Forgejo API client does not (currently) allow ignoring certificate errors.
-> When connecting through `https://`, the Forgejo host must supply certificates trusted by the Terraform host.
+> When connecting through `https://`, the Forgejo host must supply certificates trusted by the Terraform/OpenTofu host.
 > Hence, self-signed certificates must be imported locally.
 > This can be achieved by running the following command:
 >