upgrade golang add additional clients

[donseba]

This pull request introduces several updates to improve the functionality and documentation of the go-importmap package. The main changes include the addition of new funding models, the setup of a Go linter workflow, and significant enhancements to the README documentation. Additionally, new CDN clients and tests have been added to support various providers.

Enhancements to documentation:

• README.md: Simplified the package description, updated the features list, and added detailed usage examples. Removed outdated file structure information and added a new section on raw imports. [1] [2] [3] [4]

New funding models:

• .github/FUNDING.yml: Added multiple supported funding model platforms including GitHub Sponsors, Patreon, Open Collective, and more.

Workflow improvements:

• .github/workflows/golangci-lint.yml: Introduced a new GitHub Actions workflow for running golangci-lint on push and pull request events to ensure code quality.

New CDN clients and tests:

• client/esmsh/esmsh.go: Added a new client for fetching package files from esm.sh.
• client/esmsh/esmsh_test.go: Added tests for the new esm.sh client.
• client/raw/raw.go: Updated the raw provider to fetch files from a given URL.
• client/raw/raw_test.go: Added tests for the raw provider.

Code quality improvements:

• client/cdnjs/cdnjs.go: Replaced errors.New with fmt.Errorf for better error messages.
• client/jsdelivr/jsdelivr.go: Replaced errors.New with fmt.Errorf for better error messages. [1] [2]
• client/cdnjs/cdnjs_test.go: Updated tests to use t.Context(). [1] [2]
• client/jsdelivr/jsdelivr_test.go: Updated tests to use t.Context().

[Copilot]

Pull Request Overview

This pull request updates the go-importmap package to improve functionality and documentation. Key changes include the addition of new CDN clients (esm.sh, skypack, unpkg, raw), the introduction of a GitHub Actions workflow for golangci-lint, and significant enhancements to the README.

Reviewed Changes

Copilot reviewed 19 out of 19 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
.github/workflows/golangci-lint.yml	Added GitHub Actions workflow to run golangci-lint on push/PR events
client/esmsh/esmsh.go	Added new client to fetch package files from esm.sh
client/esmsh/esmsh_test.go	Added tests for the esm.sh client
client/skypack/skypack.go & _test.go	New client and tests for fetching package files from skypack
client/unpkg/unpkg.go & _test.go	New client and tests for fetching package files from unpkg
client/jsdelivr/jsdelivr.go & _test.go	Updated error message formatting and adjusted test context usage
client/cdnjs/cdnjs.go & _test.go	Updated error message formatting for improved consistency
client/raw/raw.go	Added a raw provider and its error handling
README.md	Updated package description, new sections for supported providers, and a quick example
importmap.go	Updated default shim URL and provider handling in Fetch and logging
library/package.go	Introduced the Provider interface into the Package struct

Comments suppressed due to low confidence (2)

client/raw/raw.go:24

• Consider validating the raw provider URL during initialization (in New) rather than waiting until FetchPackageFiles is called, to catch configuration errors earlier.

if p.URL == "" {

client/jsdelivr/jsdelivr.go:79

• [nitpick] Including the client name (e.g. jsdelivr) in the error message could improve clarity when debugging API response issues.

return nil, "", fmt.Errorf("client api responded with code %d", resp.StatusCode)