Upgrade GitHub Actions to resolve Node.js 20 deprecation warnings (#179)

* Upgrade GitHub Actions to resolve Node.js 20 deprecation warnings

- actions/checkout v4 → v6
- olafurpg/setup-scala v10 → v14
- coursier/cache-action v6 → v8
- actions/checkout@master → v6 in vuepress-deploy.yml

Closes #178

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Migrate olafurpg/setup-scala to coursier/setup-action

olafurpg/setup-scala is deprecated and stuck on Node.js 16.
Replace with coursier/setup-action@v2, its recommended successor.

Input changes:
- java-version: openjdk@1.17 → jvm: adoptium:17

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Add sbt to coursier/setup-action apps

coursier/setup-action only installs sbtn by default, not sbt.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* Upgrade coursier/setup-action v2 → v3 (Node.js 24)

v3.0.0 upgrades the Node.js runtime from 20 to 24.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: civilizeddev

.github/workflows/ci.yml

@@ -15,13 +15,15 @@ jobs:
       fail-fast: false
     steps:
       - name: Checkout current branch
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
       - name: Setup Scala and Java
-        uses: olafurpg/setup-scala@v10
+        uses: coursier/setup-action@v3
+        with:
+          apps: sbt
       - name: Cache scala dependencies
-        uses: coursier/cache-action@v6
+        uses: coursier/cache-action@v8
       - name: Lint code
         run: sbt check
 
@@ -30,19 +32,20 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        java: ['openjdk@1.17']
+        java: ['adoptium:17']
         scala: ['2.12.21', '2.13.18', '3.3.7']
     steps:
       - name: Checkout current branch
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
       - name: Setup Scala and Java
-        uses: olafurpg/setup-scala@v10
+        uses: coursier/setup-action@v3
         with:
-          java-version: ${{ matrix.java }}
+          jvm: ${{ matrix.java }}
+          apps: sbt
       - name: Cache scala dependencies
-        uses: coursier/cache-action@v6
+        uses: coursier/cache-action@v8
       - name: Run tests
         run: sbt ++${{ matrix.scala }}! test
 
@@ -52,15 +55,16 @@ jobs:
     if: github.event_name != 'pull_request'
     steps:
       - name: Checkout current branch
-        uses: actions/checkout@v4
+        uses: actions/checkout@v6
         with:
           fetch-depth: 0
       - name: Setup Scala and Java
-        uses: olafurpg/setup-scala@v10
+        uses: coursier/setup-action@v3
         with:
-          java-version: openjdk@1.17
+          jvm: adoptium:17
+          apps: sbt
       - name: Cache scala dependencies
-        uses: coursier/cache-action@v6
+        uses: coursier/cache-action@v8
       - name: Release artifacts
         run: sbt ci-release
         env:

.github/workflows/vuepress-deploy.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@master
+        uses: actions/checkout@v6
 
       - name: vuepress-deploy
         uses: IT4Change/vuepress-build-and-deploy@master