Bump orjson from 2.6.2 to 2.6.3 (#1458)

Bumps [orjson](https://github.com/ijl/orjson) from 2.6.2 to 2.6.3.
- [Release notes](https://github.com/ijl/orjson/releases)
- [Changelog](https://github.com/ijl/orjson/blob/master/CHANGELOG.md)
- [Commits](https://github.com/ijl/orjson/compare/2.6.2...2.6.3)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

requirements.txt

@@ -8,7 +8,7 @@ matplotlib==3.2.1
 microannotate==0.0.20
 mozci==1.2.12
 numpy==1.18.2
-orjson==2.6.2
+orjson==2.6.3
 pandas==1.0.3
 pydriller==1.12
 pyOpenSSL>=0.14  # Could not find a version that satisfies the requirement pyOpenSSL>=0.14; extra == "security" (from requests[security]>=2.7.0->libmozdata==0.1.43)