Add rustfmt check to workflow.

Signed-off-by: Jason Volk <jason@zemos.net>

docker/Dockerfile.install

@@ -1,75 +0,0 @@
-# syntax = docker/dockerfile:1.11-labs
-
-FROM input AS installer
-ARG sys_target
-ARG rust_toolchain
-ARG RUSTUP_HOME
-ARG CARGO_HOME
-ARG CARGO_TARGET
-ARG CARGO_TARGET_DIR
-ARG cargo_profile
-ARG cargo_features
-ARG cargo_args=""
-ARG crate_path="src/main"
-ARG crate_ident=""
-ARG install_temp="/usr/src/tuwunel/install"
-
-WORKDIR /usr/lib/${sys_target}
-COPY --link --from=rocksdb . .
-
-WORKDIR /usr/src/tuwunel
-RUN \
---mount=type=cache,dst=${RUSTUP_HOME},sharing=locked \
---mount=type=cache,dst=${CARGO_HOME},sharing=locked \
---mount=type=cache,dst=${CARGO_TARGET_DIR},sharing=shared \
-<<EOF
-    env
-    set -eux
-    case "$cargo_profile" in
-            "dev") profile_dir="debug";;
-           "test") profile_dir="debug";;
-        "release") profile_dir="release";;
-          "bench") profile_dir="release";;
-                *) profile_dir="$cargp_profile";;
-    esac
-
-    rustup run ${rust_toolchain} \
-        cargo install \
-            --locked \
-            --no-track \
-            --no-default-features \
-            --features "${cargo_features}" \
-            --profile "${cargo_profile}" \
-            --target "${CARGO_TARGET}" \
-            --target-dir "${CARGO_TARGET_DIR}" \
-            --root "${install_temp}" \
-            --path "${crate_path}" \
-            ${cargo_args} \
-            ${crate_ident}
-EOF
-RUN [ -f "${install_temp}/bin/tuwunel" ]
-
-
-FROM input AS install
-ARG sys_target
-ARG CARGO_INSTALL_ROOT
-ARG install_temp="/usr/src/tuwunel/install"
-
-WORKDIR /usr/lib/${sys_target}
-COPY --from=rocksdb --exclude=librocksdb.a . .
-
-WORKDIR /
-RUN \
---mount=type=bind,from=output,src=${install_temp},dst=/mnt/install \
-<<EOF
-    env
-    set -eux
-    cp -ndR --preserve=all -t ${CARGO_INSTALL_ROOT} /mnt/install/*
-EOF
-ENV bin_path="${CARGO_INSTALL_ROOT}/bin/tuwunel"
-RUN <<EOF
-    set -eux
-    ldd -v ${bin_path}
-    du -h ${bin_path}
-    sha1sum ${bin_path}
-EOF