Update version to 4.1.0

Author: SChernykh

src/util.h

@@ -35,7 +35,7 @@
 namespace p2pool {
 
 #define P2POOL_VERSION_MAJOR 4
-#define P2POOL_VERSION_MINOR 0
+#define P2POOL_VERSION_MINOR 1
 #define P2POOL_VERSION_PATCH 0
 
 constexpr uint32_t P2POOL_VERSION = (P2POOL_VERSION_MAJOR << 16) | (P2POOL_VERSION_MINOR << 8) | P2POOL_VERSION_PATCH;