Only download artifacts for primary OS/JDK

Author: armanbilge

.github/workflows/ci.yml

@@ -189,16 +189,6 @@ jobs:
           tar xf targets.tar
           rm targets.tar
 
-      - name: Download target directories (2.12.16, rootJVM)
-        uses: actions/download-artifact@v2
-        with:
-          name: target-${{ matrix.os }}-${{ matrix.java }}-2.12.16-rootJVM
-
-      - name: Inflate target directories (2.12.16, rootJVM)
-        run: |
-          tar xf targets.tar
-          rm targets.tar
-
       - name: Import signing key
         if: env.PGP_SECRET != '' && env.PGP_PASSPHRASE == ''
         run: echo $PGP_SECRET | base64 -di | gpg --import

github-actions/src/main/scala/org/typelevel/sbt/gha/GenerativePlugin.scala

@@ -615,9 +615,9 @@ ${indent(jobs.map(compileJob(_, sbt)).mkString("\n\n"), 1)}
       }
 
       val keys = "scala" :: additions.keys.toList.sorted
-      val oses = githubWorkflowOSes.value.toList
+      val oses = githubWorkflowOSes.value.toList.take(1)
       val scalas = githubWorkflowScalaVersions.value.toList
-      val javas = githubWorkflowJavaVersions.value.toList
+      val javas = githubWorkflowJavaVersions.value.toList.take(1)
       val exclusions = githubWorkflowBuildMatrixExclusions.value.toList
 
       // we build the list of artifacts, by iterating over all combinations of keys