Update actions/checkout in GitHub Actions workflows to v3 (#23)

Author: striezel

.github/workflows/aes-kw.yml

@@ -28,7 +28,7 @@ jobs:
           - thumbv7em-none-eabi
           - wasm32-unknown-unknown
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: RustCrypto/actions/cargo-cache@master
       - uses: actions-rs/toolchain@v1
         with:
@@ -51,7 +51,7 @@ jobs:
           - 1.56.0 # MSRV
           - stable
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: RustCrypto/actions/cargo-cache@master
       - uses: actions-rs/toolchain@v1
         with:

.github/workflows/workspace.yml

@@ -13,7 +13,7 @@ jobs:
   clippy:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: RustCrypto/actions/cargo-cache@master
       - uses: actions-rs/toolchain@v1
         with:
@@ -27,7 +27,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Install stable toolchain
         uses: actions-rs/toolchain@v1