Do not compile in Fedora 33

[ndias]

In file included from /usr/include/c++/10/cstdint:35,
from /usr/include/tesseract/serialis.h:22,
from /usr/include/tesseract/baseapi.h:31,
from /home/ndias/Downloads/VobSub2SRT-master/src/vobsub2srt.c++:27:
/usr/include/c++/10/bits/c++0x_warning.h:32:2: error: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support must be enabled with the -std=c++11 or -std=gnu++11 compiler options.
32 | #error This file requires compiler and library support \

[matiasw]

#67 (comment)