fix: avoid accumulating PR size labeler related labels (#97)

Author: alexisribot

src/github.sh

@@ -84,7 +84,7 @@ github::add_label_to_pr() {
   curl -sSL \
     -H "Authorization: token $GITHUB_TOKEN" \
     -H "$GITHUB_API_HEADER" \
-    -X POST \
+    -X PUT \
     -H "Content-Type: application/json" \
     -d "{\"labels\":[$comma_separated_labels]}" \
     "$GITHUB_API_URL/repos/$GITHUB_REPOSITORY/issues/$pr_number/labels" >/dev/null