feat(tests): Use official semver.org RegExp (google#5990)

Use the official semantic versioning regexp from
https://semver.org/, rather than the shorter but sloppier one
we had previously found at
https://gist.github.com/jhorsman/62eeea161a13b80e39f5249281e17c39.

tests/migration/renamings-schema.json

@@ -5,7 +5,7 @@
   "description": "A file containing information about module and module export renamings",
   "type": "object",
   "patternProperties": {
-    "^([0-9]+)\\.([0-9]+)\\.([0-9]+)(?:-([0-9A-Za-z-]+(?:\\.[0-9A-Za-z-]+)*))?(?:\\+[0-9A-Za-z-]+)?$": {"$ref": "#/$defs/version"}
+    "^(0|[1-9]\\d*)\\.(0|[1-9]\\d*)\\.(0|[1-9]\\d*)(?:-((?:0|[1-9]\\d*|\\d*[a-zA-Z-][0-9a-zA-Z-]*)(?:\\.(?:0|[1-9]\\d*|\\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?(?:\\+([0-9a-zA-Z-]+(?:\\.[0-9a-zA-Z-]+)*))?$": {"$ref": "#/$defs/version"}
   },
   "properties": {
     "develop": {"$ref": "#/$defs/version"}