gitignore: Ignore libxml2 and packagecache directory

Add more things to ignore.
8 jobs for git-more-ignore in 29 minutes and 44 seconds (queued for 4 seconds)
latest
Status Job ID Name Coverage
  Preparation
passed #440155
gst indent

00:00:18

passed #440154
manifest

00:00:41

 
  Build
passed #440156
build fedora x86_64

00:07:36

passed #440157
build nodebug fedora x86_64

00:05:58

passed #440158
build static fedora x86_64

00:14:04

passed #440159
build static nodebug fedora x86_64

00:12:07

 
  Test
passed #440160
check fedora

00:04:16

passed #440161
integration testsuites fedora

00:11:22