fix quoting which broke the release (#1115)

Author: rhuss

hack/release.sh

@@ -40,7 +40,7 @@ function build_release() {
   echo "🚧 🐳 Building the container image"
   ko resolve --strict ${KO_FLAGS} -f config/ > kn-image-location.yaml
   ARTIFACTS_TO_PUBLISH="kn-darwin-amd64 kn-linux-amd64 kn-linux-arm64 kn-windows-amd64.exe kn-image-location.yaml"
-  sha256sum "${ARTIFACTS_TO_PUBLISH}" > checksums.txt
+  sha256sum ${ARTIFACTS_TO_PUBLISH} > checksums.txt
   ARTIFACTS_TO_PUBLISH="${ARTIFACTS_TO_PUBLISH} checksums.txt"
   echo "🧮     Checksum:"
   cat checksums.txt