Fix publish: use +ci-release to cross-publish both Scala versions in single deployment

Separate ci-release calls caused duplicate artifact uploads to Central Portal, which rejects re-uploads.

Author: derrickburns

.github/workflows/publish.yml

@@ -24,16 +24,8 @@ jobs:
       - name: Set up sbt
         uses: sbt/setup-sbt@v1
 
-      - name: Publish Scala 2.13
-        run: sbt ++2.13.14 ci-release
-        env:
-          PGP_PASSPHRASE: ${{ secrets.PGP_PASSPHRASE }}
-          PGP_SECRET: ${{ secrets.PGP_SECRET }}
-          SONATYPE_USERNAME: ${{ secrets.SONATYPE_USERNAME }}
-          SONATYPE_PASSWORD: ${{ secrets.SONATYPE_PASSWORD }}
-
-      - name: Publish Scala 2.12
-        run: sbt ++2.12.18 ci-release
+      - name: Publish all Scala versions
+        run: sbt +ci-release
         env:
           PGP_PASSPHRASE: ${{ secrets.PGP_PASSPHRASE }}
           PGP_SECRET: ${{ secrets.PGP_SECRET }}