docs: update the version number #2

docs/create_a_confidential_computing_kubernetes_cluster_with_inclavare_containers.md

@@ -63,7 +63,7 @@ Note that you should install the OOT SGX driver that without ECDSA attestation.
 
    - On Ubuntu
     ```bash
-    version=0.15.1
+    version=0.15.1-1
     sudo dpkg -i occlum-pal_${version}_amd64.deb
     ```
 

docs/develop_and_deploy_hello_world_application_in_kubernetes_cluster.md

@@ -37,14 +37,14 @@ You can choose one suitable occlum SDK image from the list in [this page](https:
       - command:
         - sleep
         - infinity
-        image: docker.io/occlum/occlum:0.15.1-centos7.5
+        image: docker.io/occlum/occlum:0.15.1-centos8.1
         imagePullPolicy: IfNotPresent
         securityContext:
           privileged: true
         name: occlum-app-builder
     EOF
     ```
-    This will create a Pod with image `docker.io/occlum/occlum:0.15.1-centos7.5` and the filed `securityContext.privileged` should be set to `true`  in order to build and push docker image in container.<br />
+    This will create a Pod with image `docker.io/occlum/occlum:0.15.1-centos8.1` and the filed `securityContext.privileged` should be set to `true`  in order to build and push docker image in container.<br />
 
 - Step 2. Wait for the pod status to `Ready`