ci: bump actions/checkout from v2 to v2.3.0 (#353)

Bumps [actions/checkout](https://github.com/actions/checkout) from v2 to v2.3.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/master/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v2...b4483adec309c0d01a5435c5e24eb40de5773ad9)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/dev-image.yml

@@ -31,7 +31,7 @@ jobs:
     runs-on: ubuntu-18.04
     if: contains(github.event.head_commit.message, '[skip ci]') == false
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.0
       - run: make build
       - run: make cirun cmd="npm ci"
       - run: make ciall

.github/workflows/release.yml

@@ -9,7 +9,7 @@ jobs:
   release:
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.0
 
       - name: Dump GitHub context
         env:

.github/workflows/test.yml

@@ -28,7 +28,7 @@ jobs:
           - 'macos-latest'
           - 'windows-latest'
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v2.3.0
 
       - name: Dump GitHub context
         env:

.github/workflows/update-major-tag.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-18.04
     steps:
 
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v2.3.0
 
     - name: Update major tag
       if: github.event.release.prerelease == false