switch from --test to new --list format

As requested in scalameta/scalafmt#1459, and
introduced in scalameta/scalafmt#1466, which was
release in v2.0.1 which we pinned to in previous commit.  Yay!

Dockerfile

@@ -9,6 +9,6 @@ LABEL "repository"="https://github.com/openlawteam/scalafmt-ci"
 LABEL "homepage"="https://github.com/openlawteam/scalafmt-ci"
 LABEL "maintainer"="Matthew Rothenberg <mroth@openlaw.io>"
 
-ENTRYPOINT ["/app/scalafmt", "--non-interactive", "--test"]
+ENTRYPOINT ["/app/scalafmt", "--non-interactive", "--list"]
 # by default, github actions will set WORKDIR to $GITHUB_WORKSPACE 
 # (/github/workspace), so no need to set CMD here

Makefile

@@ -2,7 +2,7 @@ IMAGE = openlaw/scalafmt-ci
 WORKDIR = /github/workspace
 TESTDATA = .github/testdata
 
-.PHONY: image test testdata clean
+.PHONY: image test testfail testdata clean
 
 image:
 	docker build -t $(IMAGE) .
@@ -13,6 +13,11 @@ test:
 		-w=$(WORKDIR) \
 		$(IMAGE) --exclude Bad.scala
 
+testfail: ## expected failure, to see output
+	docker run --rm -it \
+		-v "$$(pwd)/.github/testdata":$(WORKDIR) \
+		-w=$(WORKDIR) \
+		$(IMAGE)
 
 # generate the "good" version of the sample file
 $(TESTDATA)/Good.scala: $(TESTDATA)/Bad.scala $(TESTDATA)/.scalafmt.conf

README.md

@@ -1,6 +1,6 @@
 # Scalafmt GitHub Action
 
-Runs `scalafmt --test` on your repository automatically with every push.
+Runs `scalafmt --list` on your repository automatically with every push.
 
 Uses [scalafmt-native](https://github.com/mroth/scalafmt-native) under the hood to keep things small and booting super quick by avoiding the JVM.