update OCP version to 4.12.26

Author: xinredhat

.tekton/pipeline-service-test.yaml

@@ -23,7 +23,7 @@ spec:
     - name: aws_region
       value: "us-east-1"
     - name: ocp_version
-      value: "4.12.22"
+      value: "4.12.26"
     - name: repo_url
       value: "{{ repo_url }}"
     - name: revision

.tekton/pipeline-service-upgrade-test.yaml

@@ -22,7 +22,7 @@ spec:
     name: upgrade-tests
   params:
     - name: ocp_version
-      value: "4.12.22"
+      value: "4.12.26"
     - name: aws_region
       value: "us-east-1"
     - name: repo_url

.tekton/stonesoup-e2e-test.yaml

@@ -20,7 +20,7 @@ spec:
     - name: aws_region
       value: "us-east-1"
     - name: ocp_version
-      value: "4.12.22"
+      value: "4.12.26"
     - name: repo_url
       value: "{{ repo_url }}"
     - name: revision