Synchronize common files from prometheus/prometheus (#1217)

* Update common Prometheus files

Signed-off-by: prombot <prometheus-team@googlegroups.com>

* Fix linting issues.

Signed-off-by: SuperQ <superq@gmail.com>

---------

Signed-off-by: prombot <prometheus-team@googlegroups.com>
Signed-off-by: SuperQ <superq@gmail.com>
Co-authored-by: SuperQ <superq@gmail.com>

Author: prombot

Makefile.common

@@ -61,7 +61,7 @@ PROMU_URL     := https://github.com/prometheus/promu/releases/download/v$(PROMU_
 SKIP_GOLANGCI_LINT :=
 GOLANGCI_LINT :=
 GOLANGCI_LINT_OPTS ?=
-GOLANGCI_LINT_VERSION ?= v2.4.0
+GOLANGCI_LINT_VERSION ?= v2.6.0
 GOLANGCI_FMT_OPTS ?=
 # golangci-lint only supports linux, darwin and windows platforms on i386/amd64/arm64.
 # windows isn't included here because of the path separator being different.

cmd/postgres_exporter/pg_setting_test.go

@@ -12,7 +12,6 @@
 // limitations under the License.
 
 //go:build !integration
-// +build !integration
 
 package main
 

cmd/postgres_exporter/postgres_exporter_integration_test.go

@@ -15,7 +15,6 @@
 // a lot of additional work to keep the external docker environment they require
 // working.
 //go:build integration
-// +build integration
 
 package main
 

cmd/postgres_exporter/postgres_exporter_test.go

@@ -12,7 +12,6 @@
 // limitations under the License.
 
 //go:build !integration
-// +build !integration
 
 package main