Bump actions/checkout from v1 to v2.3.4

.github/workflows/release.yml

@@ -10,7 +10,7 @@ jobs:
     name: Pre Release
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v2.3.4
 
       - uses: actions/setup-node@v1
         with:

.github/workflows/test.yml

@@ -17,7 +17,7 @@ jobs:
     name: Test for with parameter
     runs-on: ubuntu-18.04
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2.3.4
 
     - name: Install dependencies
       run: yarn install
@@ -48,7 +48,7 @@ jobs:
     name: Test for getting image name from enviroment variable
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v2.3.4
 
       - name: Install dependencies
         run: yarn install
@@ -78,7 +78,7 @@ jobs:
     name: Test not to create issue
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v2.3.4
 
       - name: Install dependencies
         run: yarn install

.github/workflows/unittest.yml

@@ -14,7 +14,7 @@ jobs:
     name: Test with jest
     runs-on: ubuntu-18.04
     steps:
-      - uses: actions/checkout@v1
+      - uses: actions/checkout@v2.3.4
 
       - uses: actions/setup-node@v1
         with: