Rebase (#4)

* chore(deps): bump codecov/codecov-action from 3.1.6 to 4.0.1 (TwiN#671)

Bumps [codecov/codecov-action](https://github.com/codecov/codecov-action) from 3.1.6 to 4.0.1.
- [Release notes](https://github.com/codecov/codecov-action/releases)
- [Changelog](https://github.com/codecov/codecov-action/blob/main/CHANGELOG.md)
- [Commits](codecov/codecov-action@v3.1.6...v4.0.1)

---
updated-dependencies:
- dependency-name: codecov/codecov-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

* feat(client): enhance HTTP client configuration with proxy support (TwiN#668)

* feat: enhance HTTP client configuration with proxy support

- Add `ProxyURL` field to `Config` struct with YAML tag
- Implement proxy URL parsing and setting in `getHTTPClient` method
- Add test case for `getHTTPClient` method with custom proxy URL setting
- Include `net/url` package in both `config.go` and `config_test.go` files

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* docs: enhance README with Proxy and OAuth2 Docs

- Remove empty lines from README.md
- Add documentation for proxy configuration in client examples
- Include YAML examples for client using a proxy, custom DNS resolver, OAuth2, and identity-aware proxy configurations in README.md

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>

* docs: add proxy client

Signed-off-by: appleboy <appleboy.tw@gmail.com>

* Update client/config.go

* Update README.md

* Update client/config_test.go

---------

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>
Signed-off-by: appleboy <appleboy.tw@gmail.com>
Co-authored-by: TwiN <twin@linux.com>

* chore: Update Go to 1.21

* chore(deps): bump github.com/prometheus/client_golang from 1.17.0 to 1.18.0 (TwiN#658)

chore(deps): bump github.com/prometheus/client_golang

Bumps [github.com/prometheus/client_golang](https://github.com/prometheus/client_golang) from 1.17.0 to 1.18.0.
- [Release notes](https://github.com/prometheus/client_golang/releases)
- [Changelog](https://github.com/prometheus/client_golang/blob/main/CHANGELOG.md)
- [Commits](prometheus/client_golang@v1.17.0...v1.18.0)

---
updated-dependencies:
- dependency-name: github.com/prometheus/client_golang
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

* chore(deps): bump github.com/gofiber/fiber/v2 from 2.49.2 to 2.52.1 (TwiN#682)

Bumps [github.com/gofiber/fiber/v2](https://github.com/gofiber/fiber) from 2.49.2 to 2.52.1.
- [Release notes](https://github.com/gofiber/fiber/releases)
- [Commits](gofiber/fiber@v2.49.2...v2.52.1)

---
updated-dependencies:
- dependency-name: github.com/gofiber/fiber/v2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

* docs(alerting): Fix wrong gitlab terminology (alert key vs. PAT) (TwiN#694)

Fix wrong term (alert key vs. PAT)

* chore(deps): bump github.com/TwiN/deepmerge from 0.2.0 to 0.2.1 (TwiN#684)

* chore(deps): bump github.com/TwiN/deepmerge from 0.2.0 to 0.2.1

Bumps [github.com/TwiN/deepmerge](https://github.com/TwiN/deepmerge) from 0.2.0 to 0.2.1.
- [Release notes](https://github.com/TwiN/deepmerge/releases)
- [Commits](TwiN/deepmerge@v0.2.0...v0.2.1)

---
updated-dependencies:
- dependency-name: github.com/TwiN/deepmerge
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

* build: Add `go mod tidy` in Dockerfile

* ci: Update Go to 1.20

* Update go.mod

* Update test.yml

---------

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: TwiN <twin@linux.com>

* chore(deps): bump golang.org/x/oauth2 from 0.13.0 to 0.18.0 (TwiN#701)

Bumps [golang.org/x/oauth2](https://github.com/golang/oauth2) from 0.13.0 to 0.18.0.
- [Commits](golang/oauth2@v0.13.0...v0.18.0)

---
updated-dependencies:
- dependency-name: golang.org/x/oauth2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

* feat: add mtls config to client

* feat: add mtls config to client

* Rework client tls configuration

---------

Signed-off-by: dependabot[bot] <support@github.com>
Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>
Signed-off-by: appleboy <appleboy.tw@gmail.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Bo-Yi Wu <appleboy.tw@gmail.com>
Co-authored-by: TwiN <twin@linux.com>
Co-authored-by: Salim B <git@salim.space>

client/config_test.go

@@ -107,7 +107,6 @@ func TestConfig_getHTTPClient_withCustomProxyURL(t *testing.T) {
 	}
 }
 
-
 func TestConfig_TlsIsValid(t *testing.T) {
 	tests := []struct {
 		name        string