fixing "Updates were rejected because the remote contains work that y…

…ou do"

adding git pull

ci/dependabot-pr.sh

@@ -25,6 +25,7 @@ api_base="https://api.github.com/repos/solana-labs/solana/pulls"
 pr_num=$(echo "$BUILDKITE_BRANCH" | grep -Eo '[0-9]+')
 branch=$(curl -s "$api_base/$pr_num" | python3 -c 'import json,sys;print(json.load(sys.stdin)["head"]["ref"])')
 
+git pull
 git add :**/Cargo.lock
 EMAIL="[email protected]" \
   GIT_AUTHOR_NAME="$name" \