Remove gradle publish plugin. Fix a compile errror

Author: XiaoPangxie732

build.gradle

@@ -3,7 +3,6 @@ plugins {
     id 'groovy'
 
     id 'maven-publish'
-    id 'com.gradle.plugin-publish' version '0.15.0'
 
     id 'org.cadixdev.licenser' version '0.6.1'
 }
@@ -42,19 +41,6 @@ gradlePlugin {
     }
 }
 
-pluginBundle {
-    website = 'https://github.com/MaxPixelStudios/gitpatcher'
-    vcsUrl = website
-    description = project.description
-    tags = ['git']
-
-    plugins {
-        gitpatcher {
-            displayName = 'gitpatcher'
-        }
-    }
-}
-
 publishing {
     repositories {
         maven {

src/main/groovy/org/cadixdev/gradle/gitpatcher/task/patch/PatchTask.groovy

@@ -52,6 +52,7 @@ abstract class PatchTask extends SubmoduleTask {
         return new File(repo, '.git')
     }
 
+    @Internal
     File getRefCache() {
         return new File(gitDir, '.gitpatcher_ref')
     }