Use kaniko plugin in docs as example (#4072)

pipeline/frontend/yaml/linter/linter_test.go

@@ -39,7 +39,7 @@ steps:
       - go build
       - go test
   publish:
-    image: woodpeckerci/plugin-docker-buildx
+    image: woodpeckerci/plugin-kaniko
     settings:
       repo: foo/bar
       foo: bar
@@ -61,7 +61,7 @@ steps:
       - go build
       - go test
   - name: publish
-    image: woodpeckerci/plugin-docker-buildx
+    image: woodpeckerci/plugin-kaniko
     settings:
       repo: foo/bar
       foo: bar

pipeline/frontend/yaml/utils/image_test.go

@@ -255,8 +255,8 @@ func Test_matchImage(t *testing.T) {
 			want: false,
 		},
 		{
-			from: "woodpeckerci/plugin-docker-buildx",
-			to:   "docker.io/woodpeckerci/plugin-docker-buildx",
+			from: "woodpeckerci/plugin-kaniko",
+			to:   "docker.io/woodpeckerci/plugin-kaniko",
 			want: true,
 		},
 	}