Change MangaDex UserAgent to reflect platform (#850)

Change MangaDex UserAgent to reflect platform

src/all/mangadex/build.gradle

@@ -5,7 +5,7 @@ ext {
     appName = 'Tachiyomi: MangaDex'
     pkgNameSuffix = 'all.mangadex'
     extClass = '.MangadexFactory'
-    extVersionCode = 49
+    extVersionCode = 50
     libVersion = '1.2'
 }
 

src/all/mangadex/src/eu/kanade/tachiyomi/extension/all/mangadex/Mangadex.kt

@@ -53,7 +53,7 @@ open class Mangadex(override val lang: String, private val internalLang: String,
             }.build()!!
 
     override fun headersBuilder() = Headers.Builder().apply {
-        add("User-Agent", "Tachiyomi Mozilla/5.0 (Windows NT 6.3; WOW64)")
+        add("User-Agent", "Tachiyomi "+ System.getProperty("http.agent"))
     }
 
     private fun cookiesHeader(r18Toggle: Int, langCode: Int): String {