Bump actions/checkout from 2 to 4

Bumps [actions/checkout](https://github.com/actions/checkout) from 2 to 4.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v2...v4)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/dockerhub.yml

@@ -25,7 +25,7 @@ jobs:
     steps:
 
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
 
     ##############
     # Python is used to get the program's version and generate tags
@@ -114,7 +114,7 @@ jobs:
     steps:
 
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
 
     ##############
     # Python is used to get the program's version and generate tags
@@ -202,7 +202,7 @@ jobs:
     steps:
 
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
 
     ##############
     # Python is used to get the program's version and generate tags
@@ -296,7 +296,7 @@ jobs:
     steps:
 
     - name: Checkout
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
 
     # https://github.com/peter-evans/dockerhub-description
     - name: Update repo description

.github/workflows/pypi.yml

@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@v4
     - name: Set up Python
       uses: actions/setup-python@v2
       with: