Make v1.8 1.8.0-dev again

This reverts a commit that was inadvertently merged into v1.8 from master

Author: alcaeus

phongo_version.h

@@ -18,9 +18,9 @@
 #define PHONGO_VERSION_H
 
 /* clang-format off */
-#define PHP_MONGODB_VERSION "1.9.0-dev"
+#define PHP_MONGODB_VERSION "1.8.0beta2-dev"
 #define PHP_MONGODB_STABILITY "devel"
-#define PHP_MONGODB_VERSION_DESC 1,9,0,0
+#define PHP_MONGODB_VERSION_DESC 1,8,0,2
 /* clang-format on */
 
 #endif /* PHONGO_VERSION_H */