Add hexpire (#3)

* Add hexpire command

* Do this just so I can get the git dependency to install on ioredis

* Didn't work

* Try -5

* Fix arity and keyStop

* fix: regenerate `hexpire` with `npm run gen`

Original implementation by @mlb5000

---------

Co-authored-by: Pavel Pashov <pavel.pashov@redis.com>

Author: mlb5000

lib/commands.json

@@ -686,6 +686,16 @@
     "keyStop": 1,
     "step": 1
   },
+  "hexpire": {
+    "arity": -6,
+    "flags": [
+      "write",
+      "fast"
+    ],
+    "keyStart": 1,
+    "keyStop": 1,
+    "step": 1
+  },
   "hget": {
     "arity": 3,
     "flags": [