chore: update dependencies to inlude ajv-formats (#484)

In this PR https://github.com/cloudevents/sdk-javascript/pull/471/files#diff-7ae45ad102eab3b6d7e7896acd08c427a9b25b346470d7bc6507b6481575d519R128
it was not noticed that the addition of `ajv-formats` to devDependencies
is insufficient. Unfortunately, users of v6.0.0 will receive an error when
using the module, unless they explicitly install `ajv-formats` in their
project. This commit fixes that, and should result in an immediate release
of version 6.0.1.

Signed-off-by: Lance Ball <lball@redhat.com>

package.json

@@ -111,6 +111,7 @@
   "homepage": "https://github.com/cloudevents/sdk-javascript#readme",
   "dependencies": {
     "ajv": "^8.6.3",
+    "ajv-formats": "^2.1.1",
     "util": "^0.12.4",
     "uuid": "^8.3.2"
   },
@@ -126,7 +127,6 @@
     "@typescript-eslint/eslint-plugin": "^4.29.0",
     "@typescript-eslint/parser": "^4.29.0",
     "ajv-cli": "^5.0.0",
-    "ajv-formats": "^2.1.1",
     "axios": "^0.26.1",
     "chai": "~4.2.0",
     "eslint": "^7.32.0",