web_api: Consider Semver

[nathaniel-brough]

I'm not sure how stable the web api is going to be but would it make sense to semver it. e.g.
Rather than;

curl -L https://introspector.oss-fuzz.com/api/far-reach-but-low-coverage?project=json-c

It'd be something like;

curl -L https://introspector.oss-fuzz.com/api/v1.0.0/far-reach-but-low-coverage?project=json-c

I'd be ok with only one version being supported at any one point and then if you use an old version you'd get back a deprecated response. Something like;

$ curl -L https://introspector.oss-fuzz.com/api/v0.9.0/far-reach-but-low-coverage?project=json-c
{
  "result": "API version v0.9.0 is deprecated, please use v1.0.0",
}