use latest rustc version for rustlib
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 63ad16d..f219ffe 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -398,7 +398,7 @@
     needs: compiler
     runs-on: ubuntu-22.04
     env:
-      TOOLCHAIN_VERSION: 1.65.0
+      TOOLCHAIN_VERSION: 1.81.0
     steps:
       - uses: actions/checkout@v4