Remove scripts/release.sh because of no longer used

scripts/release.sh is used for release plugins manually (by
maintainer's hand), previously. Now we introduced automated release
process by github action, hence it is no longer used and no longer
maintained. This change removes this file. Thanks, release.sh for a
long time!

Signed-off-by: Tomofumi Hayashi <tohayash@redhat.com>

scripts/release.sh

@@ -1,49 +0,0 @@
-#!/usr/bin/env sh
-set -xe
-
-SRC_DIR="${SRC_DIR:-$PWD}"
-DOCKER="${DOCKER:-docker}"
-GOLANG="${GOLANG:-golang:1.23-alpine}"
-
-TAG=$(git describe --tags --dirty)
-RELEASE_DIR=release-${TAG}
-
-BUILDFLAGS="-ldflags '-extldflags -static -X github.com/containernetworking/plugins/pkg/utils/buildversion.BuildVersion=${TAG}'"
-
-OUTPUT_DIR=bin
-
-# Always clean first
-rm -Rf ${SRC_DIR}/${RELEASE_DIR}
-mkdir -p ${SRC_DIR}/${RELEASE_DIR}
-mkdir -p ${OUTPUT_DIR}
-
-$DOCKER run -ti -v ${SRC_DIR}:/go/src/github.com/containernetworking/plugins:z --rm "${GOLANG}" \
-/bin/sh -xe -c "\
-    apk --no-cache add bash tar;
-    cd /go/src/github.com/containernetworking/plugins; umask 0022;
-
-    for arch in amd64 arm arm64 ppc64le s390x mips64le riscv64; do \
-        rm -f ${OUTPUT_DIR}/*; \
-        CGO_ENABLED=0 GOARCH=\$arch ./build_linux.sh ${BUILDFLAGS}; \
-        for format in tgz; do \
-            FILENAME=cni-plugins-linux-\$arch-${TAG}.\$format; \
-            FILEPATH=${RELEASE_DIR}/\$FILENAME; \
-            tar -C ${OUTPUT_DIR} --owner=0 --group=0 -caf \$FILEPATH .; \
-        done; \
-    done;
-
-    rm -rf ${OUTPUT_DIR}/*; \
-    CGO_ENABLED=0 GOARCH=amd64 ./build_windows.sh ${BUILDFLAGS}; \
-    for format in tgz; do \
-        FILENAME=cni-plugins-windows-amd64-${TAG}.\$format; \
-        FILEPATH=${RELEASE_DIR}/\$FILENAME; \
-        tar -C ${OUTPUT_DIR} --owner=0 --group=0 -caf \$FILEPATH .; \
-    done;
-
-
-    cd ${RELEASE_DIR};
-      for f in *.tgz; do sha1sum \$f > \$f.sha1; done;
-      for f in *.tgz; do sha256sum \$f > \$f.sha256; done;
-      for f in *.tgz; do sha512sum \$f > \$f.sha512; done;
-    cd ..
-    chown -R ${UID} ${OUTPUT_DIR} ${RELEASE_DIR}"