[Buildkite] Change commit author of commits in gh-pages to autheliabot. (#662)

.buildkite/steps/syncdoc.sh

@@ -13,9 +13,12 @@ popd
 COMMIT=$(git show -s --format=%h)
 
 pushd authelia
+git config user.name "Authelia[bot]"
+git config user.email "autheliabot@gmail.com"
+
 git add -A
 git commit -m "Synchronize docs of commit: ${COMMIT}"
 git push
 popd
 
-rm -rf authelia
+rm -rf authelia