[Identity] Update the keytar dependency (Azure#14740)

Prebuilt binaries for alpine were added in this release.

Author: orgads

sdk/identity/identity/package.json

@@ -98,7 +98,7 @@
     "uuid": "^8.3.0"
   },
   "optionalDependencies": {
-    "keytar": "^7.3.0"
+    "keytar": "^7.6.0"
   },
   "devDependencies": {
     "@azure/eslint-plugin-azure-sdk": "^3.0.0",