docs: remove RELEASE_VERSION from trivy.repo (aquasecurity#6546)

docs/getting-started/installation.md

@@ -10,11 +10,10 @@ In this section you will find an aggregation of the different ways to install Tr
     Add repository setting to `/etc/yum.repos.d`.
 
     ``` bash
-    RELEASE_VERSION=$(grep -Po '(?<=VERSION_ID=")[0-9]' /etc/os-release)
     cat << EOF | sudo tee -a /etc/yum.repos.d/trivy.repo
     [trivy]
     name=Trivy repository
-    baseurl=https://aquasecurity.github.io/trivy-repo/rpm/releases/$RELEASE_VERSION/\$basearch/
+    baseurl=https://aquasecurity.github.io/trivy-repo/rpm/releases/\$basearch/
     gpgcheck=1
     enabled=1
     gpgkey=https://aquasecurity.github.io/trivy-repo/rpm/public.key