Per https://ferd.ca/you-ve-got-to-upgrade-rebar3.html we must provide our own http adapter so we can ensure ssl opts are set. Note that we can provide the default hex core httpc adapter ssl options, however having a custom adapter will provide us greater flexibility long term. This especially true in the case of custom repositories for which the edge cases around ssl are unknown.
Added rebar3_hex_httpc_adapter copied from rebar3.
Changed rebar3_hex_config to use rebar3_hex_httpc_adapter instead of the default hex_core http adapter
Changed test/support/test_utils.erl to work with rebar3 version 3.16
Changed .github/workflows/ci.yml to only test against 3.16.1
Fixed a bug in rebar3_hex_docs where our call to rebar3_hex_client:delete_docs/3 had wrong expectations
Suppressed some dialyzer warnings that should be fixed up in a subsequent PR
Per https://ferd.ca/you-ve-got-to-upgrade-rebar3.html we must provide our own http adapter so we can ensure ssl opts are set. Note that we can provide the default hex core httpc adapter ssl options, however having a custom adapter will provide us greater flexibility long term. This especially true in the case of custom repositories for which the edge cases around ssl are unknown.