perf(lib/pluginutils): cache rc version regex

[Fdawgs]

Regex is expensive to create and garbage collect, so this should help a tad rather than having to create a new regexp object every time a plugin version is checked.

Checklist

• run npm run test and npm run benchmark
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[jsumners]

I am willing to bet this gets optimized out automatically.

[gurgunday]

From what I know, and I read it on some blog sometime ago, the // syntax gets optimized very fast as it restricts dynamic expressions inside, contrary to the RegExp constructor

[mcollina]

lgtm

I generally got burned a few times by the internal state that is retained by running the same regexp multiple times, and I totally forget that it is safe to do so sometimes.