Change Pipelines v1beta1 API in example test to v1 API

Author: khrm

test/testdata/slsa/v1/pipeline-output-image.json

@@ -13,7 +13,7 @@
         "builder": {
             "id": "https://tekton.dev/chains/v2"
         },
-        "buildType": "tekton.dev/v1beta1/PipelineRun",
+        "buildType": "tekton.dev/v1/PipelineRun",
         "invocation": {
             "configSource": {},
             "parameters": {

test/testdata/slsa/v1/task-output-image.json

@@ -13,7 +13,7 @@
         "builder": {
             "id": "https://tekton.dev/chains/v2"
         },
-        "buildType": "tekton.dev/v1beta1/TaskRun",
+        "buildType": "tekton.dev/v1/TaskRun",
         "invocation": {
             "configSource": {},
             "parameters": {}

test/testdata/slsa/v2/task-output-image.json

@@ -13,7 +13,7 @@
         "builder": {
             "id": "https://tekton.dev/chains/v2"
         },
-        "buildType": "https://chains.tekton.dev/format/slsa/v2alpha1/type/tekton.dev/v1beta1/TaskRun",
+        "buildType": "https://chains.tekton.dev/format/slsa/v2alpha1/type/tekton.dev/v1/TaskRun",
         "invocation": {
             "configSource": {},
             "parameters": {