fix: Zero length frames in old version of Node

resolves aws#199

In Node.js versions 10.9 and older will fail to decrypt if decipher.update is not called.
nodejs/node#22538 fixes this.

If the content is empty, push an empty buffer.

modules/decrypt-node/src/decipher_stream.ts

@@ -160,6 +160,10 @@ export function getDecipherStream () {
       decipherState = {} as any
 
       decipher.setAuthTag(authTag)
+      /* In Node.js versions 10.9 and older will fail to decrypt if decipher.update is not called.
+       * https://github.com/nodejs/node/pull/22538 fixes this.
+       */
+      if (!content.length) decipher.update(Buffer.alloc(0))
 
       const clear: Buffer[] = []
       for (const cipherChunk of content) {