Bump com.uber.nullaway:nullaway from 0.13.4 to 0.13.6 (#1686)

Bumps [com.uber.nullaway:nullaway](https://github.com/uber/NullAway) from 0.13.4 to 0.13.6.
- [Release notes](https://github.com/uber/NullAway/releases)
- [Changelog](https://github.com/uber/NullAway/blob/master/CHANGELOG.md)
- [Commits](uber/NullAway@v0.13.4...v0.13.6)

---
updated-dependencies:
- dependency-name: com.uber.nullaway:nullaway
  dependency-version: 0.13.6
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

gradle/libs.versions.toml

@@ -54,7 +54,7 @@ ktfmt = "0.62"
 log4j = "2.17.1"
 msgpack = "0.9.12"
 nexusPublishPlugin = "2.0.0"
-nullaway = "0.13.4"
+nullaway = "0.13.6"
 nullawayPlugin = "3.0.0"
 nuValidator = "26.5.29"
 paguro = "3.10.3"