Add vcpkg cache step

.github/workflows/ci.yml

@@ -52,6 +52,15 @@ jobs:
         if: matrix.java == 'temurin@17' && steps.setup-java-temurin-17.outputs.cache-hit == 'false'
         run: sbt +update
 
+      - name: Cache vcpkg
+        uses: actions/cache@v4
+        with:
+          key: ${{ runner.os }}-sbt-vcpkg
+          path: |
+            ~/Library/Caches/sbt-vcpkg/vcpkg-install
+            ~/.cache/sbt-vcpkg/vcpkg-install
+            ~/.cache/sbt-vcpkg/vcpkg
+
       - name: Check that workflows are up to date
         run: sbt githubWorkflowCheck
 

build.sbt

@@ -20,6 +20,24 @@ ThisBuild / scalacOptions ++= Seq(
   "-language:implicitConversions"
 )
 
+ThisBuild / githubWorkflowBuildPreamble += {
+  import org.typelevel.sbt.gha.*
+  import WorkflowStep.*
+
+  val paths =
+    List(
+      "~/Library/Caches/sbt-vcpkg/vcpkg-install",
+      "~/.cache/sbt-vcpkg/vcpkg-install",
+      "~/.cache/sbt-vcpkg/vcpkg"
+    )
+
+  Use(
+    UseRef.Public("actions", "cache", "v4"),
+    name = Some("Cache vcpkg"),
+    params = Map("key" -> "${{ runner.os }}-sbt-vcpkg", "path" -> paths.mkString("\n"))
+  )
+}
+
 val Scala3 = "3.4.1"
 ThisBuild / scalaVersion := Scala3 // the default Scala