updates: fix source code URL on _WIN32

src/common/updates.cpp

@@ -101,7 +101,7 @@ namespace tools
   {
     const char *base = user ? "https://downloads.getmonero.org/" : "https://updates.getmonero.org/";
 #ifdef _WIN32
-    static const char *extension = strncmp(buildtag.c_str(), "install-", 8) ? ".zip" : ".exe";
+    static const char *extension = strncmp(buildtag.c_str(), "source", 6) ? (strncmp(buildtag.c_str(), "install-", 8) ? ".zip" : ".exe") : ".tar.bz2";
 #else
     static const char extension[] = ".tar.bz2";
 #endif