Upgrade to go 1.18 for generics parsing support

[b2ku]

Is your feature request related to a problem? Please describe.
Unable to swag init --parseDependency where deps are using generic features

% swag init --parseDependency
...
2022/03/16 12:38:37 ParseFile error:/path/to/package@v0.1.0/something.go:8:16: expected '(', found '[' (and 7 more errors)

Describe the solution you'd like
The ability to init swagger docs with dependencies that use generic language features

Describe alternatives you've considered
Cloning and updating the go.mod to 1.18 and compiling locally for the time being.

Additional context
n/a

[b2ku]

related to #1104 (comment) I tried compiling swag with 1.18 and it passes my prior error but is unable to find the new alias any:

swag init --parseDependency
...
2022/03/16 12:45:52 ParseComment error in file /path/to/package@v0.1.0/something.go :cannot find type definition: any

[ubogdan]

I see building swag against go 1.18 is not enough.

[b2ku]

For what its worth, swapping out the any alias with interface{} gets around the error. This only works if you control the libraries which likely isn't possible in all cases.

[b2ku]

@ubogdan i've put togther an adhoc fix for myself here b2ku@6d3d4c9 in addition to bumping to 1.18

It seems to work with my own packages that use any judiciously. I don't have a good working knowledge of swag so I don't know if this sort of change is worth a PR.

[al4669]

I've also noticed it fails when you have any type constraint declarations in your code:

type Number interface {
	int32 | int64
}

error: expected ';', found '|' (and 1 more errors)

[applejag]

@rdlaitila I hope you don't mind that I publishes your changes as a PR in #1168.

It's not released yet, so in the meantime you can do the following to install the Go 1.18 compatible version of Swaggo:
Edit: It's now released and available since v1.8.1:

go install github.com/swaggo/swag/cmd/swag@v1.8.1

[b2ku]

@jilleJr no problem. I was not sure those changes were even structurally or logically sound for swag so I was hesitant. TY!

[hcsaustrup]

I had the same issue, and it seems parsing of the actual code was fixed with v1.8.1. The // @success 200 {object} model.Response[SomeType] annotation still fails when attempting to specify a generic struct as a response object. Is the syntax for describing a generic struct response documented anywhere? :-)

[applejag]

@hcsaustrup Deserves a separate issue IMO. The PR was only fixing the fact that swaggo would fail to parse Go 1.18 code to begin with and did not understand the new any keyword.

To parse generic types in the swaggo comments would be a different story, I presume, and would involve a bit more technical details.