Bump applicationinsights-core from 2.3.0 to 2.3.1

Bumps [applicationinsights-core](https://github.com/Microsoft/ApplicationInsights-Java) from 2.3.0 to 2.3.1.
- [Release notes](https://github.com/Microsoft/ApplicationInsights-Java/releases)
- [Changelog](https://github.com/Microsoft/ApplicationInsights-Java/blob/master/CHANGELOG.md)
- [Commits](microsoft/ApplicationInsights-Java@2.3.0...v2.3.1)

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

build.gradle

@@ -158,7 +158,7 @@ dependencies {
 
     errorproneJavac 'com.google.errorprone:javac:1.8.0-u20'
 
-    compile group: 'com.microsoft.azure', name: 'applicationinsights-core', version: '2.3.0'
+    compile group: 'com.microsoft.azure', name: 'applicationinsights-core', version: '2.3.1'
     compile group: 'com.microsoft.azure', name: 'applicationinsights-logging-log4j2', version: '2.3.0'
 
     testImplementation 'org.junit.jupiter:junit-jupiter:5.4.0'