docs: Change TC build status badge links (JetBrains#1750)

TC build status badge was following default branch at teamcity.jetbrains.com.
Now it tracks default branch at exposed.teamcity.com.

docs/README.md

@@ -4,7 +4,7 @@
 
 [![JetBrains team project](https://jb.gg/badges/team.svg)](https://confluence.jetbrains.com/display/ALL/JetBrains+on+GitHub)
 [![Kotlinlang Slack Channel](https://img.shields.io/badge/slack-@kotlinlang/exposed-yellow.svg?logo=slack?style=flat)](https://kotlinlang.slack.com/archives/C0CG7E0A1)
-[![TC Build status](https://teamcity.jetbrains.com/app/rest/builds/buildType:(id:KotlinTools_Exposed_Build)/statusIcon)](https://teamcity.jetbrains.com/viewType.html?buildTypeId=KotlinTools_Exposed_Build&guest=1)
+[![TC Build status](https://exposed.teamcity.com/app/rest/builds/buildType:id:Exposed_Build/statusIcon.svg)](https://exposed.teamcity.com/viewType.html?buildTypeId=Exposed_Build&guest=1)
 [![Maven Central](https://maven-badges.herokuapp.com/maven-central/org.jetbrains.exposed/exposed-core/badge.svg)](https://maven-badges.herokuapp.com/maven-central/org.jetbrains.exposed/exposed-core)
 [![GitHub License](https://img.shields.io/badge/license-Apache%20License%202.0-blue.svg?style=flat)](https://www.apache.org/licenses/LICENSE-2.0)