ci: bump actions to Node 24 runtimes

GitHub deprecated Node 20 actions — runners will force Node 24 from
June 2nd 2026 and remove Node 20 entirely on September 16th 2026.
Move every flagged action to its Node-24 release line:

- actions/checkout        v4     -> v6
- Swatinem/rust-cache     v2.8.2 -> v2.9.1
- actions/upload-artifact v4     -> v7
- actions/download-artifact v4   -> v7

dtolnay/rust-toolchain@v1 and softprops/action-gh-release@v2 were not
flagged and stay as-is.

Note: upload/download-artifact v5+ require Actions Runner 2.327.1 or
newer. GitHub-hosted runners already satisfy this; self-hosted ones
need to be up-to-date.

Author: bitxwave

.github/workflows/build.yml

@@ -36,7 +36,7 @@ jobs:
             runner: windows-11-arm
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Install Rust toolchain
         uses: dtolnay/rust-toolchain@v1
@@ -45,7 +45,7 @@ jobs:
           targets: ${{ matrix.target }}
 
       - name: Cache cargo
-        uses: Swatinem/rust-cache@v2.8.2
+        uses: Swatinem/rust-cache@v2.9.1
         with:
           key: ${{ matrix.target }}
 

.github/workflows/release.yml

@@ -38,7 +38,7 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
 
       - name: Install Rust toolchain
         uses: dtolnay/rust-toolchain@v1
@@ -47,7 +47,7 @@ jobs:
           targets: ${{ matrix.target }}
 
       - name: Cache cargo
-        uses: Swatinem/rust-cache@v2.8.2
+        uses: Swatinem/rust-cache@v2.9.1
         with:
           key: ${{ matrix.target }}
           shared-key: release
@@ -120,7 +120,7 @@ jobs:
           echo "PACKAGE_PATH=release/$out" >> $GITHUB_ENV
 
       - name: Upload artifact
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v7
         with:
           name: ${{ matrix.target }}
           path: ${{ env.PACKAGE_PATH }}
@@ -134,7 +134,7 @@ jobs:
 
     steps:
       - name: Download artifacts
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v7
         with:
           path: artifacts