Update common Prometheus files (#292)

Signed-off-by: prombot <[email protected]>

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.