updating babelstream spack package

[august-knox]

Description

Updating babelstream package to extend the newest implementation of the upstreamed spack package. Depends on PR #623 to update the spack version.

Adding/modifying a benchmark (docs: Adding a Benchmark)

• (optional) If package upstreamed to Spack is insufficient, add/modify repo/benchmark_name/package.py
• (optional) If application upstreamed to Ramble is insufficient, add/modify repo/benchmark_name/application.py
• Tags in Ramble's application.py or in repo/benchmark_name/application.py will appear in the docs catalogue
• Add/modify an experiments/benchmark_name/experiment.py to define a single node and multi-node experiments