Update README and guides to use latest disa version (#605)

Author: AleksandarSavchev

README.md

@@ -89,7 +89,7 @@ diki run \
     --config=config.yaml \
     --provider=gardener \
     --ruleset-id=disa-kubernetes-stig \
-    --ruleset-version=v2r3
+    --ruleset-version=v2r4
 ```
 
 - Run a specific rule defined in a ruleset for a known provider
@@ -98,7 +98,7 @@ diki run \
     --config=config.yaml \
     --provider=gardener \
     --ruleset-id=disa-kubernetes-stig \
-    --ruleset-version=v2r3 \
+    --ruleset-version=v2r4 \
     --rule-id=242414
 ```
 

example/guides/disa-k8s-stig-shoot.yaml

@@ -9,7 +9,7 @@ providers:
   rulesets:
   - id: disa-kubernetes-stig
     name: DISA Kubernetes Security Technical Implementation Guide
-    version: v2r3
+    version: v2r4
     ruleOptions:
     - ruleID: "242393"
       args: