docs: Fix broken link on learning Rego in README

Fixes open-policy-agent/opa#8026

Signed-off-by: Anders Eknert <[email protected]>

Author: anderseknert

README.md

@@ -7,8 +7,8 @@ write tests for your Kubernetes configuration, Tekton pipeline definitions, Terr
 Serverless configs or any other config files.
 
 Conftest uses the Rego language from [Open Policy Agent](https://www.openpolicyagent.org/) for writing
-the assertions. You can read more about Rego in [How do I write policies](https://www.openpolicyagent.org/docs/how-do-i-write-policies.html)
-in the Open Policy Agent documentation.
+the assertions. You can read more about Rego in the [Policy Language](https://www.openpolicyagent.org/docs/policy-language)
+section in the Open Policy Agent documentation.
 
 Here's a quick example. Save the following as `policy/deployment.rego`: