Reverted Dockerfile to Swift-based images

Author: username0x0a

Dockerfile

@@ -1,20 +1,15 @@
 # syntax=docker/dockerfile:1
 
-# Base image and static SDK have to be updated together.
-FROM --platform=$BUILDPLATFORM swift:6.0.3 AS builder
-WORKDIR /workspace
-RUN swift sdk install \
-	https://download.swift.org/swift-6.0.3-release/static-sdk/swift-6.0.3-RELEASE/swift-6.0.3-RELEASE_static-linux-0.0.1.artifactbundle.tar.gz \
-	--checksum 67f765e0030e661a7450f7e4877cfe008db4f57f177d5a08a6e26fd661cdd0bd
+# Swift official image with arm64 support
+# https://hub.docker.com/r/arm64v8/swift/
+ARG SWIFT_IMAGE=swift:focal
 
+FROM $SWIFT_IMAGE AS builder
 COPY . /workspace
-ARG TARGETPLATFORM
-RUN --mount=type=cache,target=/workspace/.build,id=build-$TARGETPLATFORM \
-	./Scripts/build-linux-release.sh && \
-	cp /workspace/.build/release/swiftformat /workspace
+WORKDIR /workspace
+RUN swift build -c release && mv `swift build -c release --show-bin-path`/swiftformat /workspace
 
-# https://github.com/nicklockwood/SwiftFormat/issues/1930
-FROM ubuntu:24.04 AS runner
-COPY --from=builder /workspace/swiftformat /usr/bin/swiftformat
-ENTRYPOINT [ "/usr/bin/swiftformat" ]
+FROM $SWIFT_IMAGE-slim AS runner
+COPY --from=builder /workspace/swiftformat /usr/bin
+ENTRYPOINT [ "swiftformat" ]
 CMD ["."]