feat: add support for Azure Functions v4

[KnorpelSenf]

Adds a new webook adapter following https://learn.microsoft.com/en-us/azure/azure-functions/functions-node-upgrade-v4

Fixes #737

[KnorpelSenf]

That is what I meant by my comment in #742 (review) :)

[mildronize]

@KnorpelSenf I see, actually i don't know which prop is used, or I should be something like this

export type AzureAdapterV4 = (request: {}, context: {}) => ReqResHandler<{
    status: number;
    body?: string;
} | {
    jsonBody: string;
}>;

[KnorpelSenf]

No worries, I can fix it up later today.

[KnorpelSenf]

@mildronize please check again

[mildronize]

@KnorpelSenf After I've check out the new code from the latest commit from #738, (Commit id: 8f9e16e5114421dc0dacab51f899f7d4538f0184)

you checkout the code from here: https://github.com/mildronize/grammy-azure-functions-test/tree/44221d1b5b0f0589347403d4636b9d19fa504874/func-v4

the request type error:

Argument of type 'HttpRequest' is not assignable to parameter of type '{ headers: Headers; json(): Promise<Update>; }'.
  The types returned by 'headers[Symbol.iterator]()' are incompatible between these types.
    Property '[Symbol.iterator]' is missing in type 'SpecIterator<[string, string], any, undefined>' but required in type 'HeadersIterator<[string, string]>

[mildronize]

I've found that the Azure v4, request type is mismatched, however, azure v3 is ok now.

[mildronize]

Oh, I comment the wrong place, here is what I mentioned in the comment below.

[KnorpelSenf]

I'll fix this up soon