docs(datasource/aws-rds): improve readme

lib/modules/datasource/aws-rds/readme.md

@@ -1,9 +1,17 @@
 This datasource returns the database engine versions available for use on [AWS RDS](https://aws.amazon.com/rds/) via the AWS API.
+
 Generally speaking, all publicly released database versions are available for use on RDS.
 However, new versions may not be available on RDS for a few weeks or months after their release while AWS tests them.
 In addition, AWS may pull existing versions if serious problems arise during their use.
 
-**AWS API configuration**
+<!-- prettier-ignore -->
+!!! warning
+
+    The default versioning of the `aws-rds` datasource is _not_ compatible with [AWS Aurora](https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/CHAP_AuroraOverview.html)!
+    If you use AWS Aurora, you must set your own custom versioning.
+    Scroll down to see an example.
+
+### AWS API configuration
 
 Since the datasource uses the AWS SDK for JavaScript, you can configure it like other AWS Tools.
 You can use common AWS configuration options, for example:
@@ -14,9 +22,7 @@
 
 Read the [AWS Developer Guide - Configuring the SDK for JavaScript](https://docs.aws.amazon.com/sdk-for-javascript/v3/developer-guide/configuring-the-jssdk.html) for more information on these configuration options.
 
-The minimal IAM privileges required for this datasource are:
-
-```json
+```json title="Minimal IAM privileges needed for this datasource"
 {
   "Sid": "AllowDBEngineVersionLookup",
   "Effect": "Allow",
@@ -27,14 +33,14 @@
 
 Read the [AWS RDS IAM reference](https://docs.aws.amazon.com/service-authorization/latest/reference/list_amazonrds.html) for more information.
 
-**Usage**
+### Usage
 
 Because Renovate has no manager for the AWS RDS datasource, you need to help Renovate by configuring the custom manager to identify the RDS dependencies you want updated.
 
 When configuring the custom manager, you have to pass a [filter](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-rds/interfaces/describedbengineversionscommandinput.html#filters) as minified JSON as the `packageName`.
 For example:
 
 ```yaml
 # Getting the latest supported MySQL 5.7 version from RDS as a filter would look like:
 
 [
@@ -53,9 +59,7 @@
 [{"Name":"engine","Values":["mysql"]},{"Name":"engine-version","Values":["5.7"]}]
 ```
 
-Here's an example of using the custom manager to configure this datasource:
-
-```json
+```json title="Using a custom manager to configure this datasource"
 {
   "customManagers": [
     {
@@ -72,8 +76,35 @@
 
 The configuration above matches every YAML file, and recognizes these lines:
 
 ```yaml
 spec:
   # amiFilter=[{"Name":"engine","Values":["mysql"]},{"Name":"engine-version","Values":["5.7"]}]
   engineVersion: 5.7.34
 ```
+
+#### Using Terraform, `aws-rds` datasource and Aurora MySQL
+
+Here is the Renovate configuration to use Terraform, `aws-rds` and Aurora MySQL:
+
+```json
+{
+  "customManagers": [
+    {
+      "description": "Update RDS",
+      "customType": "regex",
+      "fileMatch": [".+\\.tf$"],
+      "matchStrings": [
+        "\\s*#\\s*renovate:\\s*amiFilter=(?<lookupName>.+?) depName=(?<depName>.*) versioning=(?<versioning>.*)\\s*.*_version\\s*=\\s*\"(?<currentValue>.*)\""
+      ],
+      "datasourceTemplate": "aws-rds"
+    }
+  ]
+}
+```
+
+The above configuration will ...insert explanation of bits below...
+
+```
+# renovate:amiFilter=[{"Name":"engine","Values":["aurora-mysql"]},{"Name":"engine-version","Values":["8.0"]}] depName=aurora-mysql versioning=loose
+engine_version = "8.0.mysql_aurora.3.05.2"
+```