fix: bump errorproneVersion from 2.15.0 to 2.16

Bumps `errorproneVersion` from 2.15.0 to 2.16.

Updates `error_prone_check_api` from 2.15.0 to 2.16
- [Release notes](https://github.com/google/error-prone/releases)
- [Commits](google/error-prone@v2.15...v2.16)

Updates `error_prone_core` from 2.15.0 to 2.16
- [Release notes](https://github.com/google/error-prone/releases)
- [Commits](google/error-prone@v2.15...v2.16)

Updates `error_prone_test_helpers` from 2.15.0 to 2.16
- [Release notes](https://github.com/google/error-prone/releases)
- [Commits](google/error-prone@v2.15...v2.16)

---
updated-dependencies:
- dependency-name: com.google.errorprone:error_prone_check_api
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: com.google.errorprone:error_prone_core
  dependency-type: direct:production
  update-type: version-update:semver-minor
- dependency-name: com.google.errorprone:error_prone_test_helpers
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

build.gradle.kts

@@ -11,7 +11,7 @@ plugins {
 
 group = "jp.skypencil.errorprone.slf4j"
 
-val errorproneVersion = "2.15.0"
+val errorproneVersion = "2.16"
 
 dependencies {
     compileOnly("com.google.errorprone:error_prone_check_api:$errorproneVersion")