MT#61451 GH: raise workflow actions to v4

Artifact actions v3 will be closing down by January 30, 2025, see
https://github.blog/changelog/2024-11-05-notice-of-breaking-changes-for-github-actions/ +
https://github.blog/changelog/2024-04-16-deprecation-notice-v3-of-the-artifact-actions/

Migrate actions/upload-artifact@v2 to actions/upload-artifact@v4
as documented at
https://github.com/actions/upload-artifact/blob/main/docs/MIGRATION.md

NOTE: We need unique artifact names, otherwise we'd try to overwrite
existing artifacts. But in v4 the artifacts are immutable unless
deleted, so it would fail the build. We could also overwrite them via
`overwrite: true`, but it's useful to have artifacts for both bookworm
*and* sid available, so adapt their naming accordingly.

While at it, also bump actions/checkout@v2 to actions/checkout@v4

Change-Id: If59e7a07111bf4f92ebab70a500c92cb729c45d7

.github/workflows/debpkg.yml

@@ -13,21 +13,21 @@ jobs:
 
     steps:
     - name: Checkout source
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
 
     - name: Execute Docker debpkg action
       uses: ./.github/actions/debpkg-bookworm
 
     - name: Store Debian package artifacts
-      uses: actions/upload-artifact@v2
+      uses: actions/upload-artifact@v4
       with:
-        name: Debian binary package files
+        name: Debian binary package files for bookworm
         path: '*.deb'
 
     - name: Store Debian package build info
-      uses: actions/upload-artifact@v2
+      uses: actions/upload-artifact@v4
       with:
-        name: Debian buildinfo file
+        name: Debian buildinfo file for bookworm
         path: '*.buildinfo'
 
   build-deb-sid:
@@ -36,19 +36,19 @@ jobs:
 
     steps:
     - name: Checkout source
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
 
     - name: Execute Docker debpkg action
       uses: ./.github/actions/debpkg-sid
 
     - name: Store Debian package artifacts
-      uses: actions/upload-artifact@v2
+      uses: actions/upload-artifact@v4
       with:
-        name: Debian binary package files
+        name: Debian binary package files for sid
         path: '*.deb'
 
     - name: Store Debian package build info
-      uses: actions/upload-artifact@v2
+      uses: actions/upload-artifact@v4
       with:
-        name: Debian buildinfo file
+        name: Debian buildinfo file for sid
         path: '*.buildinfo'

.github/workflows/tests.yml

@@ -13,7 +13,7 @@ jobs:
 
     steps:
     - name: Checkout source
-      uses: actions/checkout@v2
+      uses: actions/checkout@v4
 
     - name: Display original shellcheck version
       run: shellcheck --version