Use actions/checkout@v3 rather than top of tree

.github/workflows/ci.yml

@@ -21,7 +21,7 @@ jobs:
         rust: [nightly, beta, stable]
 
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v3
 
     - name: Install ${{ matrix.rust }}
       uses: actions-rs/toolchain@v1
@@ -85,7 +85,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v3
 
     - name: setup
       run: |
@@ -102,7 +102,7 @@ jobs:
     name: Check tokio02 feature
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v3
     - name: check tokio02
       uses: actions-rs/cargo@v1
       with:
@@ -122,7 +122,7 @@ jobs:
           - arm-linux-androideabi
 
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v3
 
     - name: Install nightly
       uses: actions-rs/toolchain@v1
@@ -150,7 +150,7 @@ jobs:
         rust: [nightly, beta, stable]
 
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v3
 
     - name: Install rust with wasm32-unknown-unknown
       uses: actions-rs/toolchain@v1
@@ -181,7 +181,7 @@ jobs:
     name: Checking fmt and docs
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@master
+    - uses: actions/checkout@v3
 
     - uses: actions-rs/toolchain@v1
       with: