fix(deps): bump @salesforce/ts-types from 1.5.20 to 1.5.21

Bumps [@salesforce/ts-types](https://github.com/forcedotcom/ts-types) from 1.5.20 to 1.5.21.
- [Release notes](https://github.com/forcedotcom/ts-types/releases)
- [Changelog](https://github.com/forcedotcom/ts-types/blob/v1.5.21/CHANGELOG.md)
- [Commits](https://github.com/forcedotcom/ts-types/commits/v1.5.21)

---
updated-dependencies:
- dependency-name: "@salesforce/ts-types"
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -12,7 +12,7 @@
     "lib/**/*.d.ts"
   ],
   "dependencies": {
-    "@salesforce/ts-types": "^1.5.20",
+    "@salesforce/ts-types": "^1.5.21",
     "sinon": "^5.1.1",
     "tslib": "^2.2.0"
   },

yarn.lock

@@ -586,10 +586,10 @@
   resolved "https://registry.npmjs.org/@salesforce/prettier-config/-/prettier-config-0.0.2.tgz#ded39bf7cb75238edc9db6dd093649111350f8bc"
   integrity sha512-KExM355BLbxCW6siGBV7oUOotXvvVp0tAWERgzUkM2FcMb9fWrjwXDrIHc8V0UdDlA3UXtFltDWgN+Yqi+BA/g==
 
-"@salesforce/ts-types@^1.5.20":
-  version "1.5.20"
-  resolved "https://registry.npmjs.org/@salesforce/ts-types/-/ts-types-1.5.20.tgz#f6875a710ceca48223b240026a14af6d3b39882f"
-  integrity sha512-Ov6um4CWd63EvkRavkHG0J/P9XYL55sdkDWPMr7+AIgqh5flHxDRz09/C4e9M94aX30rzJxW4TVX6EBf4Cu2BQ==
+"@salesforce/ts-types@^1.5.21":
+  version "1.5.21"
+  resolved "https://registry.npmjs.org/@salesforce/ts-types/-/ts-types-1.5.21.tgz#e62784872f0e74bf4ae13381dc58aa4644ee2df3"
+  integrity sha512-qG8r8WOzqpFOHaH3EGU3IwGrY/pSv9NQp4B0wGxOuPDBbraXVvd3KhWVStxaLGKBkJClJ7/+t+iCSP82sEiGcg==
   dependencies:
     tslib "^2.2.0"