Update Go to v1.17

.github/aur/flux-go/PKGBUILD.template

.github/aur/flux-scm/PKGBUILD.template

.github/workflows/bootstrap.yaml

.github/workflows/e2e-arm64.yaml

.github/workflows/e2e-azure.yaml

.github/workflows/e2e.yaml

.github/workflows/release.yaml

.github/workflows/update.yaml

Dockerfile

cmd/flux/check_test.go

cmd/flux/create_source_git_test.go

cmd/flux/export_test.go

cmd/flux/helmrelease_test.go

cmd/flux/image_test.go

cmd/flux/kustomization_test.go

cmd/flux/logs_test.go

cmd/flux/main_e2e_test.go

cmd/flux/main_unit_test.go

cmd/flux/trace_test.go

cmd/flux/tree_kustomization_test.go