add arm v5 builds (jpillora#395)

Bump to Go 1.21 (jpillora#440)

Co-authored-by: cmeng <cmenginnz@gmail.com>

update dependabot

switch to scratch image

Merge pull request jpillora#315 from Taknok/keepalive

Fix keepalive

split release job into binaries/docker image

Merge pull request jpillora#246 from pbstriker38/multi_architecture_i…

…mage_build

Multi architecture image build

display client ip in verbose server logs (closes jpillora#233)

go dropped support for mips64p32, ppc, s390

support android retries