CI: Consistently use actions/checkout@v2

v2 is the current version of the checkout action and faster than v1.

.github/workflows/compliance.yml

@@ -21,7 +21,7 @@ jobs:
     env:
       H2SPEC_VERSION: '2.6.0'
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
     - 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

.github/workflows/musl.yml

@@ -13,7 +13,7 @@ jobs:
       container:
         image: alpine:latest
       steps:
-      - uses: actions/checkout@master
+      - uses: actions/checkout@v2
       - 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

.github/workflows/openssl-nodeprecated.yml

@@ -21,7 +21,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
     - name: Install VTest
       run: |
         scripts/build-vtest.sh