CI: Update to actions/checkout@v3

No functional change, but we should keep this current.
diff --git a/.github/workflows/codespell.yml b/.github/workflows/codespell.yml
index 3b31141..2243d8b 100644
--- a/.github/workflows/codespell.yml
+++ b/.github/workflows/codespell.yml
@@ -11,7 +11,7 @@
   codespell:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - uses: codespell-project/codespell-problem-matcher@v1
     - uses: codespell-project/actions-codespell@master
       with:
diff --git a/.github/workflows/compliance.yml b/.github/workflows/compliance.yml
index 148ea28..1105abb 100644
--- a/.github/workflows/compliance.yml
+++ b/.github/workflows/compliance.yml
@@ -21,7 +21,7 @@
     env:
       H2SPEC_VERSION: '2.6.0'
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Install h2spec
       run: |
         curl -fsSL https://github.com/summerwind/h2spec/releases/download/v${H2SPEC_VERSION}/h2spec_linux_amd64.tar.gz -o h2spec.tar.gz
diff --git a/.github/workflows/contrib.yml b/.github/workflows/contrib.yml
index 480f61b..99a1576 100644
--- a/.github/workflows/contrib.yml
+++ b/.github/workflows/contrib.yml
@@ -10,7 +10,7 @@
   build:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Compile admin/halog/halog
       run: |
         make admin/halog/halog
diff --git a/.github/workflows/coverity.yml b/.github/workflows/coverity.yml
index 0c4b2d0..e208c8c 100644
--- a/.github/workflows/coverity.yml
+++ b/.github/workflows/coverity.yml
@@ -24,7 +24,7 @@
       # parameters at whitespaces, without taking quoting into account.
       COVERITY_SCAN_BUILD_COMMAND: "make CC=clang TARGET=linux-glibc USE_ZLIB=1 USE_PCRE=1 USE_PCRE_JIT=1 USE_LUA=1 USE_OPENSSL=1 USE_QUIC=1 USE_SYSTEMD=1 USE_WURFL=1 WURFL_INC=addons/wurfl/dummy WURFL_LIB=addons/wurfl/dummy USE_DEVICEATLAS=1 DEVICEATLAS_SRC=addons/deviceatlas/dummy USE_51DEGREES=1 51DEGREES_SRC=addons/51degrees/dummy/pattern ADDLIB=\"-Wl,-rpath,$HOME/opt/lib/\" SSL_LIB=${HOME}/opt/lib SSL_INC=${HOME}/opt/include DEBUG+=-DDEBUG_STRICT=1 DEBUG+=-DDEBUG_USE_ABORT=1"
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Install apt dependencies
       run: |
         sudo apt-get update
diff --git a/.github/workflows/musl.yml b/.github/workflows/musl.yml
index aba3f4e..5a6b46a 100644
--- a/.github/workflows/musl.yml
+++ b/.github/workflows/musl.yml
@@ -13,7 +13,7 @@
       container:
         image: alpine:latest
       steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Install dependencies
         run: apk add gcc make tar git python3 libc-dev linux-headers pcre-dev pcre2-dev openssl-dev lua5.3-dev grep socat curl
       - name: Install VTest
diff --git a/.github/workflows/openssl-nodeprecated.yml b/.github/workflows/openssl-nodeprecated.yml
index e423f58..e7f7ffa 100644
--- a/.github/workflows/openssl-nodeprecated.yml
+++ b/.github/workflows/openssl-nodeprecated.yml
@@ -21,7 +21,7 @@
   test:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - name: Install VTest
       run: |
         scripts/build-vtest.sh
diff --git a/.github/workflows/vtest.yml b/.github/workflows/vtest.yml
index a9e86b6..e413b20 100644
--- a/.github/workflows/vtest.yml
+++ b/.github/workflows/vtest.yml
@@ -23,7 +23,7 @@
     outputs:
       matrix: ${{ steps.set-matrix.outputs.matrix }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Generate Build Matrix
         id: set-matrix
         run: python3 .github/matrix.py "${{ github.event_name }}"
@@ -44,7 +44,7 @@
       ASAN_OPTIONS: log_path=asan.log
       OT_CPP_VERSION: 1.6.0
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
       with:
         fetch-depth: 100
 #
diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index de9a00f..3d03461 100644
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -35,7 +35,7 @@
           - USE_THREAD=1
           - USE_ZLIB=1
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v3
     - uses: msys2/setup-msys2@v2
       with:
         install: >-