Update check-jsonschema URL and version

[sirosen]

👋 Hi, check-jsonschema maintainer here!

I'm doing some searches to try to find high-profile repos still using the old repo URL, so that we can get it updated across as many projects as possible.

I also enabled these in CI (previously skipped), as the ci.skip config appears to originate with a version of the hook which did not work in pre-commit.ci (v0.6.0 by the repo history). Since v0.8.x , running in pre-commit.ci is supported and should work for you. But please let me know if you try it out and run into issues!