Merge branch v3.0 into master

.github/PULL_REQUEST_TEMPLATE.md

.github/workflows/build.yaml

.github/workflows/check_doc.yml

.github/workflows/documentation.yml

.github/workflows/test-unit.yaml

.github/workflows/validate.yaml

.golangci.yml

.goreleaser.yml

.semaphore/semaphore.yml

CHANGELOG.md

LICENSE.md

README.md

build.Dockerfile

cmd/configuration.go

cmd/healthcheck/healthcheck.go

cmd/internal/gen/main.go

cmd/traefik/logger.go

cmd/traefik/plugins.go

cmd/traefik/traefik.go

cmd/traefik/traefik_test.go