Pre-fetch polyglot snapshot

There's no way to configure extensions.xml to use a snapshot repo,
other than the global settings.xml, so we prefetch it manually.

.github/workflows/ci.yml

@@ -29,10 +29,12 @@ jobs:
           distribution: 'zulu'
           java-version: ${{ matrix.java-version }}
           cache: 'maven'
+      - name: prefetch-polyglot
+        run: "cd .. ; mvn -B dependency:get -Dartifact=io.takari.polyglot:polyglot-ruby:0.4.11-SNAPSHOT -DremoteRepositories=central::default::https://repo.maven.apache.org/maven2,snapshots::::https://oss.sonatype.org/content/repositories/snapshots ; cd -"
       - name: bootstrap
         run: mvn -Pbootstrap clean package
       - name: bundle install
-        run: bin/jruby --dev -S bundle install
+        run: bin/jruby -B --dev -S bundle install
       - name: Save bootstrap build
         id: cache-bootstrap-save
         uses: actions/cache/save@v3