Add method field on Match object for page.on('metric')

[ankur22]

What?

This change adds a new field to the Match object in page.on('metric'). It allows the user to add the request method to it so that the tagging can be fine tuned to group requests with the same url and method. method is an optional field, and if it's not defined then the grouping will be done for all urls that match regardless of the request method.

page.on('metric', (metric) => {
  metric.tag({
    name:'ping-1',
    matches: [
      {url: /^http:\/\/127\.0\.0\.1\:[0-9]+\/ping\?h=[0-9a-z]+$/, method: 'GET'},
    ]
  });
});

Why?

The use case for this is when requests are made against the same URL but with different request methods. A simple example is a PUT to /cart/123 to add an item to the cart, and a GET to /cart/123 to retrieve the cart.

Checklist

• I have performed a self-review of my code
• I have added tests for my changes
• I have commented on my code, particularly in hard-to-understand areas

Related PR(s)/Issue(s)

Updates: #1450

[inancgumus]

LGTM 👍