Update Dockerfile syntax to docker/dockerfile:1 (#3534)

chore: Update Dockerfile syntax to docker/dockerfile:1

Replace docker/dockerfile-upstream:1.4.0 with docker/dockerfile:1
across all Dockerfiles, templates, test data, and documentation.

- Update DefaultDockerfileSyntax constant
- Update buildkit templates
- Update test data Dockerfiles
- Update documentation examples

Signed-off-by: Kim Christensen <[email protected]>

Author: kichristensen

docs/content/docs/bundle/custom-dockerfile.md

@@ -12,7 +12,7 @@ Sometimes you may want to full control over your bundle image, for example to in
 When you run porter create, a template Dockerfile is created for you in the current directory named **template.Dockerfile**:
 
 ```Dockerfile
-# syntax=docker/dockerfile-upstream:1.4.0
+# syntax=docker/dockerfile:1
 # This is a template Dockerfile for the bundle image
 # You can customize it to use different base images, install tools and copy configuration files.
 #
@@ -86,7 +86,7 @@ Porter automatically builds with Docker [buildkit] enabled.
 The following docker flags are supported on the [porter build] command: \--ssh, \--secret, \--build-arg.
 With these you can take advantage of Docker's support for using SSH connections, mounting secrets, and specifying custom build arguments.
 
-By default, Porter uses the [1.4.0 dockerfile syntax](https://docs.docker.com/engine/reference/builder/#syntax), but you can modify this line to use new versions as they are released.
+By default, Porter uses the [dockerfile:1 syntax](https://docs.docker.com/engine/reference/builder/#syntax), but you can modify this line to use new versions as they are released.
 
 [buildkit]: https://docs.docker.com/develop/develop-images/build_enhancements/
 [porter build]: /cli/porter_build/

pkg/build/buildkit/testdata/custom-build-arg.Dockerfile

@@ -1,4 +1,4 @@
-# syntax=docker/dockerfile-upstream:1.4.0
+# syntax=docker/dockerfile:1
 FROM --platform=linux/amd64 debian:stable-slim
 
 # PORTER_INIT

pkg/build/buildkit/testdata/template.Dockerfile

@@ -1,4 +1,4 @@
-# syntax=docker/dockerfile-upstream:1.4.0
+# syntax=docker/dockerfile:1
 FROM --platform=linux/amd64 debian:stable-slim
 
 # PORTER_INIT

pkg/build/dockerfile-generator.go

@@ -24,7 +24,7 @@ const (
 	// DefaultDockerfileSyntax is the default syntax for Dockerfiles used by Porter
 	// either when generating a Dockerfile from scratch, or when a template does
 	// not define a syntax
-	DefaultDockerfileSyntax = "docker/dockerfile-upstream:1.4.0"
+	DefaultDockerfileSyntax = "docker/dockerfile:1"
 )
 
 type DockerfileGenerator struct {

pkg/build/testdata/buildkit.Dockerfile

@@ -1,4 +1,4 @@
-# syntax=docker/dockerfile-upstream:1.4.0
+# syntax=docker/dockerfile:1
 FROM --platform=linux/amd64 debian:stable-slim
 
 ARG BUNDLE_DIR

pkg/build/testdata/custom-dockerfile-expected-output.Dockerfile

@@ -1,4 +1,4 @@
-# syntax=docker/dockerfile-upstream:1.4.0
+# syntax=docker/dockerfile:1
 FROM ubuntu:latest
 # stuff
 ARG BUNDLE_DIR

pkg/build/testdata/custom-dockerfile-without-init-expected-output.Dockerfile

@@ -1,4 +1,4 @@
-# syntax=docker/dockerfile-upstream:1.4.0
+# syntax=docker/dockerfile:1
 FROM ubuntu:latest
 ARG BUNDLE_DIR
 ARG BUNDLE_UID=65532

pkg/build/testdata/missing-args-expected-output.Dockerfile

@@ -1,4 +1,4 @@
-# syntax=docker/dockerfile-upstream:1.4.0
+# syntax=docker/dockerfile:1
 FROM ubuntu:latest
 ARG BUNDLE_DIR
 ARG BUNDLE_UID=65532

pkg/build/testdata/missing-mixins-token-expected-output.Dockerfile

@@ -1,4 +1,4 @@
-# syntax=docker/dockerfile-upstream:1.4.0
+# syntax=docker/dockerfile:1
 FROM ubuntu:light
 ARG BUNDLE_DIR
 ARG BUNDLE_UID=65532

pkg/templates/templates/build/buildkit.Dockerfile

@@ -1,4 +1,4 @@
-# syntax=docker/dockerfile-upstream:1.4.0
+# syntax=docker/dockerfile:1
 FROM --platform=linux/amd64 debian:stable-slim
 
 # PORTER_INIT