ci(lint-r): Fix lib-sums detection (#1622)

Author: eitsupi

.github/workflows/lint-r.yml

@@ -26,6 +26,7 @@ env:
   GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
   R_KEEP_PKG_SOURCE: yes
   NOT_CRAN: "true"
+  LIB_SUMS_PATH: "tools/lib-sums.tsv"
 
 jobs:
   air-format: