Update checkout action to current version.

checkout v2 uses node.js v12 which is has been recently deprecated by
github so switch to using the one on the main branch.

.github/workflows/android_test.yml

@@ -12,7 +12,7 @@ jobs:
       MAX_NAL: 28
     name: Android 8.x 9
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@main
     - name: Run CI script
       run: ./scripts/test
 
@@ -25,6 +25,6 @@ jobs:
       MAX_NAL: 30
     name: Android 10 11
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@main
     - name: Run CI script
       run: ./scripts/test

.github/workflows/coverity.yml

@@ -15,7 +15,7 @@ jobs:
       COVERITY_SCAN_BUILD_COMMAND_PREPEND: "./autogen.sh && ./configure && make dist && tar zxf libressl-*.tar.gz && rm libressl-*.tar.gz && cd libressl-* && mkdir build-static && mkdir build-shared && cmake -GNinja -DBUILD_SHARED_LIBS=ON .."
       COVERITY_SCAN_BUILD_COMMAND: "ninja"
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@main
     - name: Install apt dependencies
       run: |
         sudo apt-get update

.github/workflows/cross_test.yml

@@ -15,6 +15,6 @@ jobs:
       ARCH: ${{ matrix.arch }}
     name: ${{ matrix.arch }} - ${{ matrix.os }}
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@main
     - name: Run CI script
       run: ./scripts/test

.github/workflows/linux_test.yml

@@ -15,6 +15,6 @@ jobs:
       ARCH: native
     name: ${{ matrix.compiler }} - ${{ matrix.os }}
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@main
     - name: Run CI script
       run: ./scripts/test

.github/workflows/linux_test_asan.yml

@@ -18,6 +18,6 @@ jobs:
       CTEST_OUTPUT_ON_FAILURE: 1
     name: ${{ matrix.compiler }} - ${{ matrix.os }}
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@main
     - name: Run CI script
       run: ./scripts/test

.github/workflows/macos_test.yml

@@ -17,6 +17,6 @@ jobs:
     steps:
     - name: Install packages for macos
       run: brew install automake
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@main
     - name: Run CI script
       run: ./scripts/test

.github/workflows/regress.yml

@@ -8,7 +8,7 @@ jobs:
   rust-openssl:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@main
     - name: Install apt dependencies
       run: |
         sudo apt-get update