Update the build scripts

ballerina/build.gradle

@@ -16,19 +16,8 @@
  */
 import org.apache.tools.ant.taskdefs.condition.Os
 
-buildscript {
-    repositories {
-        maven {
-            url = 'https://maven.pkg.github.com/ballerina-platform/plugin-gradle'
-            credentials {
-                username System.getenv("packageUser")
-                password System.getenv("packagePAT")
-            }
-        }
-    }
-    dependencies {
-        classpath "io.ballerina:plugin-gradle:${project.ballerinaGradlePluginVersion}"
-    }
+plugins {
+    id 'io.ballerina.plugin'
 }
 
 description = 'Ballerina - Nats Ballerina Generator'
@@ -55,8 +44,6 @@ def stripBallerinaExtensionVersion(String extVersion) {
     }
 }
 
-apply plugin: 'io.ballerina.plugin'
-
 ballerina {
     packageOrganization = packageOrg
     module = packageName

build.gradle

@@ -17,10 +17,11 @@
  */
 
 plugins {
-    id "com.github.spotbugs" version "${spotbugsPluginVersion}"
-    id "com.github.johnrengelman.shadow" version "${shadowJarPluginVersion}"
-    id "de.undercouch.download" version "${downloadPluginVersion}"
-    id "net.researchgate.release" version "${releasePluginVersion}"
+    id 'com.github.spotbugs'
+    id 'com.github.johnrengelman.shadow'
+    id 'de.undercouch.download'
+    id 'net.researchgate.release'
+    id 'jacoco'
 }
 
 allprojects {

settings.gradle

@@ -7,6 +7,27 @@
  * in the user manual at https://docs.gradle.org/6.3/userguide/multi_project_builds.html
  */
 
+pluginManagement {
+    plugins {
+        id "com.github.spotbugs-base" version "${spotbugsPluginVersion}"
+        id "com.github.johnrengelman.shadow" version "${shadowJarPluginVersion}"
+        id "de.undercouch.download" version "${downloadPluginVersion}"
+        id "net.researchgate.release" version "${releasePluginVersion}"
+        id "io.ballerina.plugin" version "${ballerinaGradlePluginVersion}"
+    }
+
+    repositories {
+        gradlePluginPortal()
+        maven {
+            url = 'https://maven.pkg.github.com/ballerina-platform/*'
+            credentials {
+                username System.getenv("packageUser")
+                password System.getenv("packagePAT")
+            }
+        }
+    }
+}
+
 plugins {
     id "com.gradle.enterprise" version "3.2"
 }