chore: Update GitHub Actions to use checkout@v4

Author: jay-tau

.github/workflows/drishti-darshan-3.4.0.yml

@@ -12,7 +12,7 @@ jobs:
     timeout-minutes: 60
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
         with:
           submodules: true
 

.github/workflows/drishti-darshan-3.4.1.yml

@@ -12,7 +12,7 @@ jobs:
     timeout-minutes: 60
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
         with:
           submodules: true
 

.github/workflows/drishti-darshan-3.4.2.yml

@@ -12,7 +12,7 @@ jobs:
     timeout-minutes: 60
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
         with:
           submodules: true