[Buildkite] Reorder git fetch in pipeline (#697)

This will ensure that we always will have up-to-date refs for the repo post-checkout.

.buildkite/hooks/post-checkout

@@ -2,6 +2,8 @@
 
 set +u
 
+git fetch -q
+
 if [[ ! $BUILDKITE_COMMAND =~ "buildkite-agent pipeline upload" ]] || \
 [[ $BUILDKITE_COMMAND == ".buildkite/steps/e2etests.sh | buildkite-agent pipeline upload" ]]; then
   echo "--- :buildkite: Setting up Build environment"

.buildkite/steps/aurhelper.sh

@@ -1,6 +1,5 @@
 #! /bin/bash
 
-git fetch && \
 GITTAG=$(git describe --long --tags | sed 's/^v//;s/\([^-]*-g\)/r\1/;s/-/./g')
 
 echo "--- :linux: Deploy AUR package: ${PACKAGE}"

.buildkite/steps/ghartifacts.sh

@@ -12,7 +12,6 @@ do
 done
 
 echo "--- :github: Deploy artifacts for release: ${BUILDKITE_TAG}"
-git fetch
 hub release create "${BUILDKITE_TAG}" "${artifacts[@]}" -F <(echo -e "${BUILDKITE_TAG}\n\n## Changelog\n$(git log --oneline --pretty='* %h %s' $(git describe --abbrev=0 --tags $(git rev-list --tags --skip=1 --max-count=1))...$(git describe --abbrev=0 --tags))\n\n## Docker Container\n* \`docker pull authelia/authelia:${BUILDKITE_TAG//v}\`"); EXIT=$?
 
 if [[ $EXIT -eq 0 ]];