Remove JCenter() from repositories where possible (#1322)

diff --git a/build.gradle b/build.gradle
index 9d94ad8..683a698 100644
--- a/build.gradle
+++ b/build.gradle
@@ -61,7 +61,7 @@
         maven { url 'https://kotlin.bintray.com/kotlinx' }
         maven { url "https://dl.bintray.com/jetbrains/kotlin-native-dependencies" }
         maven { url 'https://maven.pkg.jetbrains.space/kotlin/p/dokka/dev' }
-        jcenter()
+        mavenCentral()
         gradlePluginPortal()
     }
 
@@ -140,7 +140,7 @@
 
     repositories {
         mavenLocal()
-        jcenter()
+        mavenCentral()
         maven { url "https://dl.bintray.com/kotlin/kotlinx" }
         // Future replacement for kotlin-dev, with cache redirector
         maven { url "https://cache-redirector.jetbrains.com/maven.pkg.jetbrains.space/kotlin/p/kotlin/dev" }
@@ -153,6 +153,7 @@
         }
         maven { url 'https://maven.pkg.jetbrains.space/kotlin/p/dokka/dev' }
         maven { url "https://dl.bintray.com/kotlin/kotlin-eap" }
+        jcenter() // blocker: https://github.com/valich/intellij-markdown/issues/64
     }
 }