feat: upgrade terraform docs using renovate

CHANGELOG.md

@@ -8,6 +8,8 @@ to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
 
+- Upgrade terraform docs docker image using renovate.
+
 ## [0.9.0] - 2024-11-13
 
 [Compare with previous version](https://github.com/sparkfabrik/terraform-gitlab-kubernetes-gitlab-agent/compare/0.8.0...0.9.0)

Makefile

@@ -1,4 +1,4 @@
-TERRAFORM_DOCS_VERSION ?= 0.18.0
+TERRAFORM_DOCS_IMAGE_TAG ?= 0.18.0
 
 .PHONY: lint tfscan generate-docs
 
@@ -12,4 +12,4 @@ generate-docs: lint
 	docker run --rm -u $$(id -u) \
 		--volume "$(PWD):/terraform-docs" \
 		-w /terraform-docs \
-		quay.io/terraform-docs/terraform-docs:$(TERRAFORM_DOCS_VERSION) markdown table --config .terraform-docs.yml --output-file README.md --output-mode inject .
+		quay.io/terraform-docs/terraform-docs:$(TERRAFORM_DOCS_IMAGE_TAG) markdown table --config .terraform-docs.yml --output-file README.md --output-mode inject .

renovate.json

@@ -1,6 +1,7 @@
 {
   "$schema": "https://docs.renovatebot.com/renovate-schema.json",
   "extends": [
-    "github>sparkfabrik/renovatebot-default-configuration"
+    "github>sparkfabrik/renovatebot-default-configuration",
+    "github>sparkfabrik/renovatebot-default-configuration//custom/terraform_docs"
   ]
 }