Update gitignore for meson
Drop all automake detritus, leave only the default build directory meson
suggests
*.o
*.pc
-*.la
-*.lo
*.swp
*~
*.sig
*.patch
*.rej
*.trs
-Makefile
-Makefile.in
-aclocal.m4
-autom4te.cache/
-config.guess
-config.h
-config.h.in
-config.log
-config.status
-config.sub
-configure
-depcomp
-install-sh
-libtool
-ltmain.sh
-missing
-stamp-h1
-.libs/
-.deps/
-src/libratbag-version.h
-doc/libratbag.doxygen
-doc/html
tags
-test-driver
-compile
-m4
-symbols-leak-test.log
-test-build-cxx
-test-build-linker
-test-build-pedantic-c99
-test-build-std-gnuc90
-test-iconv-helper
-test-suite.log
-test-context
-test-device
-test-*.log
-ratbag-command
-hidpp10-dump-page
-hidpp20-dump-page
-lur-command
+build/
