feat: add unset key script

Author: motoki317

.scripts/secret-unset-key.sh

@@ -0,0 +1,12 @@
+#!/usr/bin/env bash
+
+if [ "$#" -ne 2 ]; then
+  echo "既にsopsで暗号化されたSecretのキーを削除します。"
+  echo "Usage:   $0 filename key" >&2
+  echo "Example: $0 traq/secrets/env.yaml MY_ENV_NAME" >&2
+  exit 1
+fi
+
+set -eux
+
+sops --config .sops.yaml unset "$1" "[\"stringData\"][\"$2\"]"