build(npm): add Standard Version v9.3.2

This tool is used to generate changelogs, tag repositories and bump
version numbers across the code-base. In preparation for the v2.6.0
release of TF-A, we will be incorporating it into our release workflow,
with the hope that it can reduce some of the workload involved going
forward.

After this change our dependency license situation is as follows:

```
$ license-checker --summary
├─ MIT: 249
├─ ISC: 43
├─ Apache-2.0: 6
├─ BSD-2-Clause: 3
├─ (MIT OR CC0-1.0): 3
├─ BSD-3-Clause: 2
├─ 0BSD: 2
├─ (MIT OR Apache-2.0): 1
├─ BSD*: 1
├─ CC-BY-3.0: 1
└─ CC0-1.0: 1
```

Change-Id: Ie41443045ecff22f322d155a4bed8ab5d92208cd
Signed-off-by: Chris Kay <chris.kay@arm.com>

package.json

@@ -11,6 +11,7 @@
     "@commitlint/config-conventional": "^14.1.0",
     "commitizen": "^4.2.4",
     "cz-conventional-changelog": "^3.3.0",
-    "husky": "^7.0.4"
+    "husky": "^7.0.4",
+    "standard-version": "^9.3.2"
   }
 }