Update common Prometheus files (prometheus#590)

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

Author: prombot

.github/workflows/golangci-lint.yml

@@ -22,7 +22,7 @@ jobs:
       - name: install Go
         uses: actions/setup-go@6edd4406fa81c3da01a34fa6f6343087c207a568 # v3.5.0
         with:
-          go-version: 1.20.x
+          go-version: 1.21.x
       - name: Install snmp_exporter/generator dependencies
         run: sudo apt-get update && sudo apt-get -y install libsnmp-dev
         if: github.repository == 'prometheus/snmp_exporter'