redis-benchmarks-spec-cli: enable to Interpret PATTERN as a regular expression to filter tag names

Sample command including feature request:
Expect to only allow for 5.x.x versions
```
redis-benchmarks-spec-cli --use-tags --redis_repo ~/redislabs/redis --from-date 2009-01-01 --tags-regex '5\.\d+\.\d+$'
```