Happymh: Add referer header for image requests (#2135)

src/zh/happymh/build.gradle

@@ -1,7 +1,7 @@
 ext {
     extName = 'Happymh'
     extClass = '.Happymh'
-    extVersionCode = 8
+    extVersionCode = 9
 }
 
 apply from: "$rootDir/common.gradle"

src/zh/happymh/src/eu/kanade/tachiyomi/extension/zh/happymh/Happymh.kt

@@ -154,6 +154,13 @@ class Happymh : HttpSource(), ConfigurableSource {
 
     override fun imageUrlParse(response: Response): String = throw UnsupportedOperationException()
 
+    override fun imageRequest(page: Page): Request {
+        val header = headersBuilder()
+            .set("Referer", "$baseUrl/")
+            .build()
+        return GET(page.imageUrl!!, header)
+    }
+
     override fun setupPreferenceScreen(screen: PreferenceScreen) {
         val context = screen.context