[fix] brand - partial revert of e82e37ce6

In commit e82e37ce6 accidentally the brand file was touched / partial
revert::

  export GIT_URL='https://github.com/searxng/searxng'
  export GIT_BRANCH='master'

Related: https://github.com/searxng/searxng/pull/515

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

utils/brand.env

@@ -1,5 +1,5 @@
 export SEARXNG_URL=''
 export SEARXNG_PORT='8888'
 export SEARXNG_BIND_ADDRESS='127.0.0.1'
-export GIT_URL='https://github.com/return42/searxng'
-export GIT_BRANCH='doc-theme'
+export GIT_URL='https://github.com/searxng/searxng'
+export GIT_BRANCH='master'