discrepancies between matchers syntax in pact-go and matcher syntax in pact-protobuf-plugin

Hello - thank you for your work on the project!

Here are the matching rules that I thought would work everywhere https://github.com/pact-foundation/pact-plugins/blob/main/docs/matching-rule-definition-expressions.md

The pact-go repo has quite a lot of testcases.

syntax supported

I see discrepancies between the 2 syntax supported.

example in pact-protobuf-plugin's readme

"email", "matching(regex, '\\w+@[a-z0-9\\.]+', 'test@ourtest.com')"

example syntax in pact-go's matching test code

{
"pact:matcher:type": "regex",
"value": "myawesomeword",
"regex": "\\w+"
}

matching on maps

example in pact-go's consumer docs

Matcher	Min. Compatibility	Description
...	...	...
`EachKeyLike(key, template)`	V3	Object where the key itself is ignored, but the value template must match. Useful for dynamic keys.
...	...	...

matcher struct in pact-go

type eachKeyLike struct {
    Specification models.SpecificationVersion `json:"pact:specification"`
    Type          string                      `json:"pact:matcher:type"`
    Contents      interface{}                 `json:"value"`
}

pact-protobuf-plugin's readme section "matching on map fields"

You could define a test like

    "request": {
        "labels": {
          "pact:match": "eachKey(matching(regex, '\\d+', '')), eachValue(matching(regex, '(\\w|\\s)+', '')), atLeast(1)",
          "100": "this is a label"
        },
        "ok": "true"
    }

So I don't know if I'm just looking at way old docs in pact-go and just expecting similar syntax to work everywhere, including with pact-protobuf-plugin or if that's an area where we could improve.

for context, in case someone wants to spend time fixing it

ideal situation (for me)

https://github.com/pact-foundation/pact-go/blob/master/examples/consumer_v4_test.go

I really liked the builder approach and the different matchers that are there for the HTTP side of things / plain json:

...
WillRespondWith(200, func(b *consumer.V4ResponseBuilder) {
    b.
        Header("Content-Type", S("application/json")).
        JSONBody(Map{
            "datetime":       Regex("2020-01-01", "[0-9\\-]+"),
            "name":           S("Billy"),
            "lastName":       S("Sampson"),
            "superstring":    Includes("foo"),
            "id":             Integer(12),
            "accountBalance": Decimal(123.76),
            "itemsMinMax":    ArrayMinMaxLike(27, 3, 5),
            "itemsMin":       ArrayMinLike("thereshouldbe3ofthese", 3),
            "equality":       Equality("a thing"),
            "arrayContaining": ArrayContaining([]interface{}{
                Like("string"),
                Integer(1),
                Map{
                    "foo": Like("bar"),
                },
            }),
        })
}).
...

and I wish we had the same syntax sugar for GRPC interactions.

pactflow / pact-protobuf-plugin