[v3-0-test] Make the link to SBOM relative to the sbom documentation (#52875) (#52878)

When we "hard-coded" the link we had to hard-code the version and
it did not work for staging (because we had link to prod site)

With this PR:

* no more hard-coding
* works on staging
(cherry picked from commit 1d1b1d4c83765b11be1f0b769bbee20535712fe9)
diff --git a/airflow-core/docs/security/sbom.rst b/airflow-core/docs/security/sbom.rst
index 744cba2..0f1d699 100644
--- a/airflow-core/docs/security/sbom.rst
+++ b/airflow-core/docs/security/sbom.rst
@@ -27,5 +27,5 @@
 
 By default, Apache Airflow SBOM files are generated for Airflow core with all providers. In the near future we aim at generating SBOM files per provider and also provide them for docker standard images.
 
-Each airflow version has its own SBOM files, one for each supported python version.
-You can find them `here <https://airflow.apache.org/docs/apache-airflow/|version|/sbom/>`_.
+Each Airflow version has its own SBOM files, one for each supported python version.
+You can find them `here <../sbom/>`_.