feat: Add Java install if using act

For some reason, I need to pin the Java install when using act. This is not
needed when using the GitHub Actions runner, so add an escape clause to
only run this extra step when using act.

.github/workflows/example.yml

@@ -37,6 +37,11 @@ jobs:
       - run: npm ci
       - run: npm run build
       - run: npm run package
+      - uses: actions/setup-java@v2
+        if: ${{ env.ACT }}
+        with:
+          java-version: 11
+          distribution: zulu
       - uses: ./
         with:
           version: ${{ matrix.nextflow_version }}
@@ -55,5 +60,10 @@ jobs:
       - run: npm ci
       - run: npm run build
       - run: npm run package
+      - uses: actions/setup-java@v2
+        if: ${{ env.ACT}}
+        with:
+          java-version: 11
+          distribution: zulu
       - uses: ./
       - run: nextflow -v