Implement GitHub packages upload

Needs testing tho.

Author: Andre601

build.gradle

@@ -72,4 +72,19 @@ publishing{
             artifact sourcesJar
         }
     }
-}
+    repositories{
+        maven{
+            name = "GitHubPackages"
+            url = uri("https://maven.pkg.github.com/botblock/JavaBotBlockAPI")
+            credentials{
+                username = "botblock"
+                password = System.getenv("GITHUB_TOKEN")
+            }
+        }
+        publications{
+            gpr(MavenPublications){
+                from(components.java)
+            }
+        }
+    }
+}