net-mgmt/prometheus: Update from 1.6.3 to 1.7.1

[joneum]

Summary

• net-mgmt/prometheus: Update from 1.6.3 to 1.7.1

• Changelog: https://github.com/prometheus/prometheus/releases/tag/v1.7.0 https://github.com/prometheus/prometheus/releases/tag/v1.7.1

PR: 220056
Submitted by: jevonearth (ports at ecadlabs.com) (maintainer)
Approved by: xxx (mentor)
#Differential Revision: https://reviews.freebsd.org/Dxxxxx

Test Plan

:~/dev/ports/net-mgmt/prometheus % portlint -AC
WARN: Makefile: [0]: possible direct use of command "install" found. use ${INSTALL_foobaa} instead.
WARN: Makefile: [0]: possible direct use of command "install" found. use ${INSTALL_foobaa} instead.
WARN: Makefile: for new port, make $FreeBSD$ tag in comment section empty, to make SVN happy.
0 fatal errors and 3 warnings found.

poudriere testport:

10amd64
10i386
11amd64
11i386
12.0-CURRENT r318899 amd64
12.0-CURRENT r318400 i386