CI: Ignore rust-toolchain and use latest nightly

.github/workflows/build_rpi3.yml

@@ -31,6 +31,7 @@ jobs:
           ruby-version: "2.7"
       - name: Set up Rust nightly
         run: |
+          rm rust-toolchain
           rustup self update
           rustup toolchain install nightly --component llvm-tools-preview
           rustup default nightly

.github/workflows/build_rpi4.yml

@@ -31,6 +31,7 @@ jobs:
           ruby-version: "2.7"
       - name: Set up Rust nightly
         run: |
+          rm rust-toolchain
           rustup self update
           rustup toolchain install nightly --component llvm-tools-preview
           rustup default nightly

.github/workflows/sanity.yml

@@ -33,6 +33,7 @@ jobs:
           npm install prettier
       - name: Set up Rust nightly
         run: |
+          rm rust-toolchain
           rustup self update
           rustup toolchain install nightly --component rustfmt clippy
           rustup default nightly

.github/workflows/test_integration.yml

@@ -31,6 +31,7 @@ jobs:
           ruby-version: "2.7"
       - name: Set up Rust nightly
         run: |
+          rm rust-toolchain
           rustup self update
           rustup toolchain install nightly --component llvm-tools-preview
           rustup default nightly

.github/workflows/test_unit.yml

@@ -31,6 +31,7 @@ jobs:
           ruby-version: "2.7"
       - name: Set up Rust nightly
         run: |
+          rm rust-toolchain
           rustup self update
           rustup toolchain install nightly --component llvm-tools-preview
           rustup default nightly