Update to actions/checkout@v3

Author: cuviper

.github/workflows/ci.yml

@@ -32,7 +32,7 @@ jobs:
             bench: test build benchmarks
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
@@ -63,7 +63,7 @@ jobs:
             target: thumbv6m-none-eabi
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
@@ -82,7 +82,7 @@ jobs:
         rust:
           - beta
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
@@ -98,7 +98,7 @@ jobs:
         rust:
           - nightly
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal