Added release task (#4423)

build.gradle

@@ -28,6 +28,7 @@ buildscript {
 }
 
 plugins {
+  id "maven-publish"
   id "com.diffplug.gradle.spotless" version "4.3.0"
   id "org.sonarqube" version "2.8"
   id "jacoco"
@@ -66,6 +67,12 @@ if (ext.branch) {
   version = version + "+branch." + ext.branch
 }
 
+ext.release = System.getenv('RELEASE') ?: ""
+if (ext.release) {
+  version = ext.release.substring(1)
+}
+
+
 // Maven group and artifact name
 group = artifact_group
 archivesBaseName = artifact_basename
@@ -136,3 +143,24 @@ minecraft {
 }
 
 apply from: 'gradle/scripts/artifacts.gradle'
+
+publishing {
+    publications {
+        maven(MavenPublication) {
+            groupId = project.group
+            artifactId = project.archivesBaseName
+            version = project.version
+            from components.java
+        }
+    }
+    repositories {
+        maven {
+            credentials {
+                username System.getenv("GITHUB_ACTOR")
+                password System.getenv("GITHUB_TOKEN")
+            }
+            name = "GitHubPackages"
+            url = "https://maven.pkg.github.com/AppliedEnergistics/Applied-Energistics-2"
+        }
+    }
+}