gitignore: add generated unity sources for lib and src #1498

Job	Run time
linux-mingw, AM gcc	2m 33s
dl-mingw, CM 9.5.0-x86_64 schannel	11m 10s
cygwin, AM x86_64 openssl R	9m 37s
linux-mingw, CM gcc	1m 22s
msvc, CM x64-windows schannel MultiSSL U	8m 42s
dl-mingw, CM 7.3.0-x86_64 schannel U	7m 59s
cygwin, CM x86_64 openssl	8m 30s
msvc, CM x64-windows openssl	9m 20s
dl-mingw, CM 6.4.0-i686 schannel !unity	3m 6s
msvc, CM x64-uwp openssl	3m 51s
msvc, CM x64-windows libressl	8m 29s
msys2, AM x86_64 !proxy	7m 33s
msvc, CM x64-windows boringssl	8m 21s
msys2, AM x86_64 default	4m 50s
msvc, CM x64-windows wolfssl	6m 49s
msys2, CM x86_64 default	6m 28s
msvc, CM x64-windows mbedtls	6m 57s
msys2, AM x86_64 default R	7m 34s
mingw, AM x86_64 default	6m 40s
mingw, AM x86_64 c-ares U	9m 59s
mingw, CM x86_64 schannel c-ares U	6m 47s
mingw, CM ucrt-x86_64 schannel R TrackMemory	2m 53s
mingw, CM clang-x86_64 openssl	2m 8s
mingw, CM ucrt-x86_64 schannel uwp	2m 47s
mingw, CM x86_64 schannel dev debug	2m 46s
mingw, CM i686 schannel R	2m 37s
	2h 39m 48s

Provide feedback