Apply suggestions from code review

Co-authored-by: Fredrik Skogman <[email protected]>
Signed-off-by: Bob Callaway <[email protected]>

Makefile

@@ -26,7 +26,7 @@ RUST_ACTION ?= run -p sigstore-protobuf-specs-codegen
 PLATFORM ?= linux/amd64
 UID ?= $(shell id -u)
 GID ?= $(shell id -g)
-DOCKER_BUILD = docker build --platform ${PLATFORM} --build-arg UID=${UID} --build-arg GID=${GID}
+DOCKER_BUILD = docker build --platform ${PLATFORM} --build-arg UID=${UID}
 DOCKER_RUN = docker run --platform ${PLATFORM} --user ${UID}:${GID}
 
 PROTOS = $(shell find protos/ -iname "*.proto" | sed 's|^|/defs/|')

protoc-builder/Dockerfile.protoc

@@ -11,12 +11,11 @@ RUN apt-get update && apt-get install -y unzip git
 
 # Set up user and group to match host we're building the container on
 ARG UID
-ARG GID
 
-RUN addgroup --gid ${GID} myuser && adduser --uid ${UID} --ingroup myuser --disabled-password myuser
+RUN adduser --uid ${UID} --disabled-password myuser
 
 # Set permissions on the output directories so the user can write to them
-RUN chown myuser:myuser /protobuf /googleapis
+RUN chown myuser /protobuf /googleapis
 
 # Switch to user to execute the remaining commands
 USER myuser
@@ -26,7 +25,7 @@ USER myuser
 ARG PROTOC_VERSION=v21.6
 ARG PROTOC_CHECKSUM=sha256:6a9fc36363a2d05d73fc363a46cd57d849068d33305db39f77daac8ba073e818
 
-ADD --chown=myuser:myuser --checksum=${PROTOC_CHECKSUM} https://github.com/protocolbuffers/protobuf/releases/download/${PROTOC_VERSION}/protoc-${PROTOC_VERSION#v}-linux-x86_64.zip /tmp/protoc.zip
+ADD --chown=myuser --checksum=${PROTOC_CHECKSUM} https://github.com/protocolbuffers/protobuf/releases/download/${PROTOC_VERSION}/protoc-${PROTOC_VERSION#v}-linux-x86_64.zip /tmp/protoc.zip
 RUN unzip -d /protobuf /tmp/protoc.zip
 RUN chmod 755 /protobuf/bin/protoc