Excavator: Consistent Gradle artifact repositories (#574)

Author: svc-excavator-bot

build.gradle

@@ -2,13 +2,10 @@ import net.ltgt.gradle.errorprone.CheckSeverity
 
 buildscript {
     repositories {
+        gradlePluginPortal()
         mavenCentral()
-        maven {
-            url 'https://dl.bintray.com/palantir/releases/'
-        }
-        maven {
-            url 'https://plugins.gradle.org/m2/'
-        }
+        maven { url 'https://palantir.bintray.com/releases' }
+        jcenter()
     }
     dependencies {
         classpath 'com.netflix.nebula:gradle-info-plugin:6.0.0'
@@ -40,9 +37,8 @@ allprojects {
 
     repositories {
         mavenCentral()
-        maven {
-            url 'https://dl.bintray.com/palantir/releases/'
-        }
+        maven { url 'https://palantir.bintray.com/releases' }
+        jcenter()
     }
 }