[testnet_conway] Bump actions/checkout to v6.0.2 and dorny/paths-filter to v4.0.1 (Node.js 24) (#6347)

## Motivation

Backport of #6345 to `testnet_conway`.

GitHub is deprecating Node.js 20 for Actions runners. Starting June 2,
2026, actions running on Node.js 20 will be forced to Node.js 24, which
may break them.

## Proposal

Bump all workflow files in `testnet_conway` to:
- `actions/checkout@v4` → `actions/checkout@v6.0.2`
- `dorny/paths-filter@v3` → `dorny/paths-filter@v4.0.1`

19 workflow files updated, 48 total replacements.

## Test Plan

CI will validate the updated actions on `testnet_conway` workflows.

## Release Plan

- Nothing to do / These changes follow the usual release cycle.

## Links

- Main branch PR: #6345
- [reviewer
checklist](https://github.com/linera-io/linera-protocol/blob/main/CONTRIBUTING.md#reviewer-checklist)

Author: ndr-ds

.github/workflows/benchmarks.yml

@@ -19,7 +19,7 @@ jobs:
     timeout-minutes: 40
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6.0.2
     - uses: actions-rust-lang/setup-rust-toolchain@v1
     - name: Clear up some space
       run: |

.github/workflows/bridge-e2e.yml

@@ -30,7 +30,7 @@ jobs:
     timeout-minutes: 60
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6.0.2
         with:
           fetch-depth: 0
           submodules: recursive

.github/workflows/build_image.yml

@@ -45,7 +45,7 @@ jobs:
     timeout-minutes: 60
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6.0.2
         with:
           fetch-depth: 0
           ref: ${{ inputs.ref }}

.github/workflows/docker-compose.yml

@@ -46,7 +46,7 @@ jobs:
     timeout-minutes: 40
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6.0.2
         with:
           fetch-depth: 0
       - uses: actions-rust-lang/setup-rust-toolchain@v1

.github/workflows/docker_image.yml

@@ -14,7 +14,7 @@ jobs:
     timeout-minutes: 60
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6.0.2
         with:
           fetch-depth: 0
 

.github/workflows/documentation.yml

@@ -40,7 +40,7 @@ jobs:
     if: github.ref == 'refs/heads/main'
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6.0.2
     - uses: actions-rust-lang/setup-rust-toolchain@v1
     - name: Install Protoc
       uses: ./.github/actions/install-protoc
@@ -60,7 +60,7 @@ jobs:
     timeout-minutes: 120
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6.0.2
     - uses: actions-rust-lang/setup-rust-toolchain@v1
     - name: Install Protoc
       uses: ./.github/actions/install-protoc

.github/workflows/dynamodb.yml

@@ -42,7 +42,7 @@ jobs:
     timeout-minutes: 40
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6.0.2
     - uses: actions-rust-lang/setup-rust-toolchain@v1
     - name: Install Protoc
       uses: ./.github/actions/install-protoc

.github/workflows/explorer.yml

@@ -31,11 +31,11 @@ jobs:
     outputs:
       should-run: ${{ steps.files-changed.outputs.paths }}
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6.0.2
         with:
           fetch-depth: 0
       - name: Filter paths
-        uses: dorny/paths-filter@v3
+        uses: dorny/paths-filter@v4.0.1
         id: files-changed
         with:
           predicate-quantifier: 'every'
@@ -56,7 +56,7 @@ jobs:
     timeout-minutes: 10
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6.0.2
     - uses: actions/setup-node@v4
     - uses: actions-rust-lang/setup-rust-toolchain@v1
     - name: Check toolchain symlinks

.github/workflows/forge-deploy-scripts.yml

@@ -20,7 +20,7 @@ jobs:
     timeout-minutes: 15
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6.0.2
         with:
           submodules: recursive
 

.github/workflows/indexer.yml

@@ -36,7 +36,7 @@ jobs:
     timeout-minutes: 15
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6.0.2
     - uses: actions-rust-lang/setup-rust-toolchain@v1
     - name: Install Protoc
       uses: ./.github/actions/install-protoc
@@ -56,7 +56,7 @@ jobs:
     timeout-minutes: 20
 
     steps:
-    - uses: actions/checkout@v4
+    - uses: actions/checkout@v6.0.2
     - uses: actions-rust-lang/setup-rust-toolchain@v1
     - name: Install Protoc
       uses: ./.github/actions/install-protoc