Linux AppImage

For get working update checking mechanism need to build with:

diff --git a/src/version.h b/src/version.h
index 12c81c2..a62e12a 100644
--- a/src/version.h
+++ b/src/version.h
@@ -1,7 +1,7 @@
 #ifndef VERSION_H
 #define VERSION_H
 
-#define APP_VERSION "git"
+#define APP_VERSION "20.0"
 
 //APP_TYPE can be:
 // - git
@@ -9,7 +9,7 @@
 // - macos
 // - appimage
 // - deb
-#define APP_TYPE "git"
+#define APP_TYPE "appimage"