CI: Upgraded version of "actions/checkout"

Author: ShaharNaveh

.github/workflows/ci.yml

@@ -22,7 +22,7 @@ jobs:
 
     steps:
     - name: Checkout
-      uses: actions/checkout@v1
+      uses: actions/checkout@v2
 
     - name: Looking for unwanted patterns
       run: ci/code_checks.sh patterns
@@ -94,7 +94,7 @@ jobs:
     steps:
 
     - name: Checkout
-      uses: actions/checkout@v1
+      uses: actions/checkout@v2
 
     - name: Set up pandas
       uses: ./.github/actions/setup
@@ -147,7 +147,7 @@ jobs:
     steps:
 
     - name: Checkout
-      uses: actions/checkout@v1
+      uses: actions/checkout@v2
 
     - name: Set up pandas
       uses: ./.github/actions/setup

.github/workflows/database.yml

@@ -56,7 +56,7 @@ jobs:
 
     steps:
     - name: Checkout
-      uses: actions/checkout@v1
+      uses: actions/checkout@v2
 
     - name: Cache conda
       uses: actions/cache@v1

.github/workflows/posix.yml

@@ -44,7 +44,7 @@ jobs:
 
     steps:
     - name: Checkout
-      uses: actions/checkout@v1
+      uses: actions/checkout@v2
 
     - name: Cache conda
       uses: actions/cache@v1