Temporarily disable the nightly build

Author: Mikhail Zabaluev

.github/workflows/main.yml

@@ -71,8 +71,9 @@ jobs:
         toolchain: [stable]
         mode: ['', '--release']
         include:
-          - os: ubuntu-latest
-            toolchain: nightly
+          # Temporarily disabled due to https://github.com/rust-lang/cargo/issues/8351
+          # - os: ubuntu-latest
+          #   toolchain: nightly
     runs-on: ${{ matrix.os }}
     timeout-minutes: 30
     env: