feat: Add the Digest field to ReleaseAsset

[suzuki-shunsuke]

Close #3627

https://github.blog/changelog/2025-06-03-releases-now-expose-digests-for-release-assets/
https://docs.github.com/en/rest/releases/releases?apiVersion=2022-11-28#get-a-release

The Get a Release API returns digests of assets.
To get digests, this commit adds the field Digest and the method GetDigest to ReleaseAsset.

[suzuki-shunsuke]

Test has passed.

$ ./script/test.sh
testing .
ok  	github.com/google/go-github/v73/github	3.617s	coverage: 99.1% of statements
	github.com/google/go-github/v73/test/fields		coverage: 0.0% of statements
?   	github.com/google/go-github/v73/test/integration	[no test files]
testing example
	github.com/google/go-github/v73/example/actionpermissions		coverage: 0.0% of statements
	github.com/google/go-github/v73/example/appengine		coverage: 0.0% of statements
	github.com/google/go-github/v73/example/basicauth		coverage: 0.0% of statements
	github.com/google/go-github/v73/example/codespaces/newreposecretwithxcrypto		coverage: 0.0% of statements
	github.com/google/go-github/v73/example/codespaces/newusersecretwithxcrypto		coverage: 0.0% of statements
	github.com/google/go-github/v73/example/commitpr		coverage: 0.0% of statements
	github.com/google/go-github/v73/example/listenvironments		coverage: 0.0% of statements
	github.com/google/go-github/v73/example/migrations		coverage: 0.0% of statements
	github.com/google/go-github/v73/example/newfilewithappauth		coverage: 0.0% of statements
	github.com/google/go-github/v73/example/newrepo		coverage: 0.0% of statements
	github.com/google/go-github/v73/example/newreposecretwithxcrypto		coverage: 0.0% of statements
	github.com/google/go-github/v73/example/ratelimit		coverage: 0.0% of statements
	github.com/google/go-github/v73/example/simple		coverage: 0.0% of statements
	github.com/google/go-github/v73/example/tokenauth		coverage: 0.0% of statements
	github.com/google/go-github/v73/example/topics		coverage: 0.0% of statements
	github.com/google/go-github/v73/example/verifyartifact		coverage: 0.0% of statements
testing scrape
ok  	github.com/google/go-github/scrape	1.234s	coverage: 59.4% of statements
	github.com/google/go-github/scrape/example/scrape		coverage: 0.0% of statements
testing tools
ok  	tools/metadata	1.280s	coverage: 81.7% of statements
testing tools/sliceofpointers
ok  	tools/sliceofpointers	1.452s	coverage: 94.7% of statements

[suzuki-shunsuke]

I've confirmed the fix works as expected.

package main

import (
	"context"
	"encoding/json"
	"log"
	"os"

	"github.com/google/go-github/v73/github"
	"golang.org/x/oauth2"
)

func main() {
	if err := run(); err != nil {
		log.Fatal(err)
	}
}

func run() error {
	ctx := context.Background()
	httpClient := oauth2.NewClient(ctx, oauth2.StaticTokenSource(
		&oauth2.Token{AccessToken: os.Getenv("GITHUB_TOKEN")},
	))
	client := github.NewClient(httpClient).Repositories
	release, _, err := client.GetRelease(ctx, "aquaproj", "aqua", 233010212)
	if err != nil {
		return err
	}
	encoder := json.NewEncoder(os.Stdout)
	encoder.SetIndent("", "  ")
	if err := encoder.Encode(release); err != nil {
		return err
	}
	return nil
}

module foo

go 1.24.5

require (
	github.com/google/go-github/v73 v73.0.0
	golang.org/x/oauth2 v0.30.0
)

replace github.com/google/go-github/v73 => github.com/suzuki-shunsuke/go-github/v73 v73.0.1-0.20250719051818-956a007e23fa

require github.com/google/go-querystring v1.1.0 // indirect

GITHUB_TOKEN=$(gh auth token) go run main.go

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.33%. Comparing base (69f5bc7) to head (956a007).
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #3628   +/-   ##
=======================================
  Coverage   91.33%   91.33%           
=======================================
  Files         184      184           
  Lines       16174    16174           
=======================================
  Hits        14773    14773           
  Misses       1227     1227           
  Partials      174      174           

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[gmlewis]

Thank you, @suzuki-shunsuke and @alexandear!
LGTM.
Merging.