capture and pass along exit code in case of failures

entrypoint.sh

@@ -21,9 +21,17 @@ while IFS=  read -r f; do
     -v "${PWD}":/home/user \
     git.lerch.org/lobo/pkcs11:1 \
     -s --id "${INPUT_SLOT}" -m SHA256-RSA-PKCS -i "$f" -o "${dest_sig}" --pin env:INPUT_USER_PIN
+  ec=$?
+  if [ $ec -ne 0 ]; then
+    exit $ec
+  fi
   if [ -n "${INPUT_PUBLIC_KEY}" ]; then
     echo "Public key specified. Uploading to sigstore public transparency log"
     rekor upload --artifact "$f" --signature "${dest_sig}" --pki-format x509 --public-key public_key
+    ec=$?
+    if [ $ec -ne 0 ]; then
+      exit $ec
+    fi
   fi
 done <<ALLFILES_INPUT
 $all_files