Run CI on stable rust, now that rust 1.68 is released

Author: jannic

.github/workflows/ci.yml

@@ -19,7 +19,7 @@ jobs:
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
-          toolchain: nightly
+          toolchain: stable
           target: ${{ matrix.target }}
           override: true
       - uses: actions-rs/cargo@v1

.github/workflows/clippy.yml

@@ -18,7 +18,7 @@ jobs:
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
-          toolchain: nightly
+          toolchain: stable
           override: true
           components: clippy
       - uses: actions-rs/clippy-check@v1

.github/workflows/cron.yml

@@ -13,7 +13,7 @@ jobs:
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
-          toolchain: nightly
+          toolchain: stable
           target: thumbv6m-none-eabi
           override: true
       - uses: actions-rs/cargo@v1

.github/workflows/rustfmt.yml

@@ -13,7 +13,7 @@ jobs:
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
-          toolchain: nightly
+          toolchain: stable
           override: true
           components: rustfmt
       - uses: actions-rs/cargo@v1