modify:gitignore and output path

.gitignore

@@ -1,2 +1,4 @@
 Build/
 *.user
+*.dll
+*.a

qcustomplot.pro

@@ -11,7 +11,7 @@ CONFIG += c++17
 # In order to do so, uncomment the following line.
 #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
 
-DESTDIR = ./../libs
+DESTDIR = ./../
 MOC_DIR = ./moc
 OBJECTS_DIR = ./objs
 RCC_DIR = ./resources